8 4 



ENTOMOLOGY 



FIG. 103. 



tera (Chrysopidae, Myrmeleonidae), and in various larvae 

 whose pupae are suspended from a silken support, as in the 



coleopterous families Coc- 

 cinellidae and Chrysomel- 

 idae (in part) and the dip- 

 terous family Syrphidae, 

 as well as most diurnal 

 Lepidoptera. 



FIG. 104. 



Head of caterpillar of Samia cecropia. a, 

 antenna; c, clypeus; /, labriim; Ip, labial palpus; 

 m, mandible; mp, maxillary palpi; o, ocelli; s, 

 spinneret. 



The silk glands of caterpillars 

 are homologous with the true 

 salivary glands of other insects, 

 opening as usual through the hy- 

 popharynx, which is modified to 

 form a spinning organ, or spin- 

 neret (Fig. 103). The silk glands 

 of Lepidoptera are a pair of long 

 tubes, one on each side of the 

 body, but often much longer than 

 the body and consequently convo- 

 luted. Thus in the silk worm 

 (Bombyx mori) they are from 

 four to five times as long as the 

 body and in Tele a polyphemus, 



Seven times aS long. In the Silk 

 . 1,1111 



worm the convoluted glandular 



portion of each tube (Fig. 104) opens into a dilatation, or silk 



reservoir, which in turn empties into a slender duct, and the 



Silk glands of the silk worm, 

 Bombyx mori. cd, common duct; 

 d, one of the paired ducts; g, g, 

 Filippi's glands; gl, gland proper; 

 p, thread press; r, reservoir. 



