THE DEVELOPMENT OP AXTS. 



73 



abdomen, i. c., to the pedicel plus the gaster of the adult. In a few 

 genera (Pscudomynna) the head, as Emery (18991') has shown, bears 

 minute vestiges of antennae. The mouth-parts are distinct and consist 

 of a pair of mandibles, a pair of fleshy maxillae and an unpaired labium. 

 Both maxilke and labium are furnished with small, conical tactile- 

 papilla; (Figs. 38-41), and the latter also bears the opening of the 

 sericteries, or spinning glands. Xo traces of eyes are visible. There 

 are ten pairs of tracheal openings, a pair each for the meso- and meta- 

 thoracic and the eight anterior abdominal segments. 



The transparent chitinous integument is very thin and easily 

 ruptured, so that handling the larvae must require considerable care 

 on the part of the ants. It is sometimes naked (Platytliyrea), but 

 much more frequently covered with chitinous hairs which in different 

 species show a bewildering di- 

 versity of form and are most 

 abundant and conspicuous in 

 young individuals. These hairs, 

 which Janet has called " poils 

 d'aecrochage," may be long, 

 simple and rigid, or flexuous, 

 helicoid, furcate or tipped with 

 single or double hooks, ramose, 

 plumose or serrate (Figs. 37- 

 43). Some species have hairs 

 of very different kinds on dif- 

 ferent parts of the body. These 

 are all adaptive structures with Fir . 3g- L arva of Lobopelta ehngata. 



well-defined functions, at least (Original.) a, Young; b. adult larva; c, head 



. .. .. of adult larva from above ; 'd. tubercle of 



in certain species. Lhe follow- young< e> tuber cle of adult larva, 

 ing are some of these functions : 



1. The hairs may serve to protect the delicate larvae from the 

 mandibles of their voracious or underfed sister larvae. 



2. They prevent the body of the larva from lying directly in con- 

 tact with the moist soil of the nest. 



3. In many Myrmicinae the pairs of very long, hooked, dorsal hairs 

 which have an S- or C-shaped flexure in their bases (Fig. 43). serve to 

 anchor the larvae to the walls of the nest, the under surfaces of stones, 

 etc. Janet (1904, p. 32) has shown that the flexure acts like a spring 

 and prevents the rupture of the thin integument when the larva is 

 hastily picked up by the ants, for when the hair is drawn out, the 

 terminal hooks have time to become inclined and release their hold. 



4. The hairs hold the young larvae together in packets and thus 



