ENTOMOLOGY 



FIG. 48. 



Hypopharynx of He- 

 mimerus talpoides. I, 

 lingua; s, superlingua. 

 After HANSEN. 



base of the hypopharynx. In the most generalized insects, 

 Thysanura and Collembola, the hypopharynx is a compound 

 organ, consisting of a median ventral lobe, or lingua, and two 

 dorso-lateral lobes, termed superlingua 

 by the author. Superlinguse occur in a 

 few other mandibulate orders (Orthop- 

 tera, Fig. 48; Ephemerida, Fig. 49), but 

 have not yet been recognized in the more 

 specialized orders of insects. 



Suctorial Types. Owing to their 

 greater complexity, suctorial mouth parts 

 are not nearly so well understood as the 

 mandibulate organs, but enough has been 

 learned to enable us to homologize the 

 two types, even though morphologists still disagree in regard 

 to minor details of interpretation. 



The suctorial, or haustellate, orders are Collembola (in 

 part), Thysanoptera (in part), Hemiptera, Trichoptera (im- 

 perfectly) , Lepidoptera, Dip- 

 tera, Siphonaptera and Hy- 

 menoptera (which have 

 functional mandibles, how- 

 ever). 



Hemiptera. -The beak, 

 or rostrum, in Hemiptera 

 consists (Fig. 50) of a 

 conspicuous, one- to four- 

 jointed labium, which en- 

 sheathes hair-like mandibles and maxillae and is covered 

 above at its base by a short labrum. The mandibles and max- 

 illae are sharply-pointed, piercing organs and the former fre- 

 quently bear retrorse barbs just behind the tip ; the two max- 

 illae lock together to form a sucking tube. Though primarily 

 a sheath, the labium bears at its extremity sensory hairs, which 

 are doubtless used to test the food. This general description 

 applies to all Hemiptera except the parasitic forms, which pre- 



Hypopharynx of an ephemerid, Hepta- 

 genia. I, lingua; si, si, superlinguae. 

 After VAYSSIERE. 



