io8 



ELEMENTARY ENTOMOLOGY 



FIG. 140. A winged pea aphis, illustrating the uni- 

 form translucent, membranous texture and vena- 

 tion of the wings of the Homoptera. (Much 

 enlarged) 



beak arises from the back of the head. 

 sita, are entirely wingless, degen- 

 erate forms which are parasitic 

 on man and other mammals. 



SUBORDER HETEROPTERA 



The aquatic bugs. Several 

 families of true bugs inhabit our 

 streams, ponds, and lakes. The 

 water-boatmen (Corisidae] are 

 from one fourth to one half an 

 inch long, and of a brownish 

 color, but appear like glistening 

 silver as they dive through the 

 water, carrying with them a thin 

 coating of air which they breathe. 

 Their near relatives, the back- 

 swimmers (Notonectidae\ differ 

 in that they swim upside down 

 on their backs, which are shaped 

 like the keel of a boat instead of 

 being flat. The water-scorpions 



A 



basal half thickened and 

 the tips membranous 

 and overlapping, while 

 the hind-wings are en- 

 tirely membranous, so 

 that the wings are unlike 

 (heteros), and the beak 

 arises from the front of 

 the head. In the other 

 principal suborder, the 

 Homoptera, the wings are 

 membranous throughout 

 and slope at the sides of 

 the body like a roof, both 

 pairs of wings being 

 alike (homoios), and the 

 third suborder, the Para- 



FIG. 141. Back-swimmers (Notonecta) 



A, A', and water-boatman (Corixa) B. 



(Slightly enlarged) 



(After Linville and Kelly) 



