Ant Larvae of Four Tribes: Second Supplement (Hymenoptera: Formicidae: Myrmicinae)

Subsequent to the publication of our first supplement on the larvae o the subfamily Myrmicinae (196oa)1 we have received ]rom other myrmecologists so much additional material that it has become necessary to publish additional supplements. TRIBE LEPTOTHORACINI Genus MACROMISCHA Roger Machromischa $ubditiva Wheeler Creighton I965Life cycle: egg 30 days, larva 23 days., pupa 19 days. Genus LEPTOTHORAX Mayr Kempf I959: 393 "The morphological distinctness o.] the imaginal stages and the distribution of the species, may even suggest to accord Nesomyrmex full generic status. The larvae, however, are quite close to the holarctic subgenus Leptothorax s. str., according to G. C. & J. Wheeler (955), who studied those of echinatinodis.’"

Head hairs o.o5-o.o38 mm long, with tip bifid. Labrum with about ten hairs, about o.o25 mm long, on the anterior surface; posterior surface with eight sensilla. Each maxillary palp a raised cluster of four sensilla; each gale'a a very short peg with two sensilla. Each labial palp with five sensilla. YOUNG SEXUAL LARVA. Length (through spiracles) ,about 3.2 mm. Similar to the above larva except as follo,ws. Body sac-like.
Dorsal surface of posterior so,mites with a ew minute spinules. Cranium transversely subelliptical. Anterior surface of labrum with four hairs.
Material studied: four worker semipupae and two young sexual larvae from Texas, courtesy o.f Dr. A. C. Cole.

Leptothorax nevadensis Wheeler
Length (through spiracles) about 2.8 mm. Similar to. L. ambiguu (955: 2) except as follows. Integument with a few minute spinules on the venter of anterior somites and the dorsa of posterior somites. Body hairs: (2) o.o25-o.9 mm long; (3) about 0.25 mm long, on AI-AIV. Head hairs o.oi3-o.o3 mm long, generally distributed. Each mandible with narrow blade and two medial teeth. Each maxilla with a ventral projection on the latera.1 surface; each palp a cluster of five sensilla. Each labial palp a cluster of five sensilla. (Material studied: six larvae from Oregon, G. C. and J. Wheeler # 8) Leptothorax n.iger splendidices Urbani  described the larva and, figured young and mature larv.ae and the head of the latter. Leptothorax  (2) about 0.25 mm long, anchor-tipped with flexuous shaft, six on the dorsum of each T2, T3, AI, AII and four on AIII. Cranium subtrapezoidal, broadest dorsally; occiput nearly flat; clypeus bulging. Antennae each with three sensilla, each of which bears a rather long spinule. Head hairs moderately numerous, 0.05-0'.075 mm long, bifid with the branches short to long. Labrum bilobed, n.armwed dorsally; each lobe with two hairs on the anterior surface about o.006 mm long, ventral border with three isolated and two contiguous sensilla, posterior surface with six isolated and a cluster o.f three .sensilla; entire posterior surface with a few short rows of minute spinules dorsally and with coarse isolated spinules ventrally. Mandibles leptothoraciform (i.e., moderately stout, tapering gradually and curving gradually to an apical tooth, anterior surface produced medially into a blade, which bears two medial teeth and a few denticles). Each maxilla paraboloidal, apex with coarse isolated spinules; each palp a cylinder with four apical and one subapical sensilla; each galea a short stout cylinder with two apical sensilla. Labium narrow, anterior surface with coarse spinules, which are isolated or in short rows near each lateral surface; each palp a slight elevation with five sensilla; an isolated sensillum between each palp and the opening of the sericteries, the latter a transverse slit. ( Labrum paraboloidal, with three small ventral projections; anterior surface with six minute hairs; ventral border with two small sensilla on each ventrolateral projection and two groups of two larger contiguous sensilla; posterior surface with 6 sensilla and scattered minute spinules. Each mandible vollenhoviform, but with only one medial tooth (i.e., slender, rather long and nearly straight, apex forming a moderately long slender tooth which is slightly curved medially; with a narrow medial blade, from the edge of which arises one inconspicuous medial tooth). Each maxilla with the apex paraboloidal and with minute isolated spinules; each palp a narrow frustum with four apical and one lateral sensilla; galea digitiform with two apical sensilla. Labium paraboloidal, with a few short rows o.f minute spinules; each palp a skewed peg with five sensilla; an isolated sensillure between each palp and the opening o.f the sericteries, the. latter a transverse slit. Hypopharynx with minute spinules in short rows. Integument of venter of anterior somites sparsely spinulo.se, the spinules minute .and in short transverse rows. Body hairs, very few: 6 on TI, 2 each on T2-AIV; o.oo8-o.o33 mm long, longest and with multifid-tip on ZI, becoming shorter and simple posteriorly. Head large; cranium subpyriform. Each antenna with three sensilla, each of which bears a spinule. Head hairs minute (about o.oo6 mm long), simple, six only, near mouth parts. Labrum twice, as. broad as long, bilobed, lateral borders curved; each lobe with five sensilla on the anterior surface, two contiguous sensilla on the ventral border, and one isolated .and three contiguous sensilla on the. posterior surface; entire posterior surface moderately spinulose, the spinules minute and in short rows which are arranged in longer subtransverse rows medially, laterally the spinules are coarser and isolated. Each mandible heavily sclerotized, narrowly subtriangular in anterior view; o.( two portions: lateral thick and terminating in a long slender apical tooth; medial blade arising from the anterior surface and bearing: two sharp-pointed medial teeth. Each maxilla with the apex conoidal and bearing a few spinules; palp a low rounded knob with five sensilla; galea, a short frustum with two, apical sensilla. Labium feebly bilobed, with minute spinules in subparallel rows; each palp a low rounded knob with five sensilla; an isolated sensillum between each palp and the opening of the sericteries, the latter a short transverse slit. Hypopharynx densely spinulose, the spinules minute and in short .arcuate rows which are arranged in long subparallel transverse ro'ws, base with numerous heavily sclerotized long-  VERY YOUNG LARVA. Length (through spiracles) about 1.6 ram. Body subellipsoidal, head on the anterior end (i.e., similar to 1.9 mm larva o C. minutus, I954 155). Otherwise similar to mature larva except in the ollowing details. Entire integument spinulose, the spinules minute and in short transverse rows. Head hairs shorter (o.o13-o.o38 mm long). Labrum with ten hairs on the anterior sura,ce. Mandibles sickle-shaped, no blade. YOUNGEST LARVA. Length (through spiracles).about mm long. Similar to young larva except as follows.. Body egg-shaped. Spiracles very small. Integument with spinules on the dorsal surface, of abdomen from spiracle to spiracle, more extensive on AIX and AX. Body hairs very sparse; (I) o.oo3-o.o25 mm long, few, none on AIX and AX: (2) o.o25-o.o75 mm long, few, with short-bifid to short-multifid tip, on lateral surfaces; (3) o.o9-o.8 mm long, four on the dorsum of each AI-AVII, with straight shaft and smooth anchor-tip. Head hairs very few, about o.0o3 mm long. Posterior surface of labrum lacking spinules. Each mandible with one apical and one medial tooth. Each maxillary palp represented by a cluster of sensilla. Labium and hypopharynx without spinules. (2) about 0.38 mm long, with short-bifid tip, about eight on the cranium. Mandibles heavily sclerotized.
Material studied: numerous larvae rom Brazil, courtesy of Dr.