352 



AN INTRODUCTION TO ENTOMOLOGY 



An important feature of the head in the Hemiptera is the extended 

 development of the gular regions, which results in the beak being 



Fig. 402. — Tracheation of a fore wing of a pentatomid nymph. 



borne by the front part of the head. This contrasts strongly with the 

 condition found in the Homoptera, where the gula is so reduced that 



Fig. 403. — Head of Leihocerus, aorsal Pig. 404. — Head of Lethocerus, ventral 

 aspect. asoect. 



the beak arises from the hind part of the lower side of the head. 



In Lethocerus the occiput (Fig. 403 , o) is separated from the vertex 



by a distinct transverse suture. The vertex (Fig. 403, v, v) is very 



