590 THE STUDY OF INSECTS, 



of attack of these parasites is between two abdominal 

 segments of the host. The presence of one of these para- 

 sites is indicated by an irregularity in the outline of the 

 abdomen of the infested wasp or bee ; and, too, the heads 

 of the pupa cases of the parasites can be seen project- 

 ing from the suture. ** The head of the pupa case of the 

 male is convex, that of the female is flat ; specimens con- 

 taining male pupae can be kept confined with proper 

 food until the parasite is hatched." (Le Conte and Horn.) 

 Two genera occur in this country, Stylops (Sty^lops), 

 which infests bees of the genus Andrena (An-dre^na), and 

 Xejios (Xe'nos)^ which infest wasps of the genus Polistes (Po- 

 lis'tes). Certain foreign genera infest ants, cockroaches, and 

 homopterous insects. 



Suborder Rhynchophora (Rhyn-choph'o-ra). 

 The Snout-beetles. 



This suborder includes the insects commonly called 

 snout-beetles, of which ten families are represented in North 

 America. With these insects the head is more or less 

 prolonged into a beak, which is sometimes longer than the re- 

 mainder of the body. The most distinctive characteristics of 

 this suborder are the absence of the gula, there being only 

 a single gular suture (Fig. 720, gs), and the fact that the 

 epimera of the prothorax meet on the middle 

 line behind the prosternum (Fig. 720). 



A monograph of the North American 

 species of this suborder by Le Conte and Horn 

 is published by the American Philosophical So- 

 ciety, Philadelphia. 



The family Rhinomacerid^ (Rhin-o-ma- 

 FiG. 720. cer'i-dae) includes a small number of Snout- 

 beetles in which the elytra have no fold on the lower sur- 

 face near the outer edge, but in which the labrum is distinct. 

 The head is prominent, not deflexed ; the snout is as long as 

 the prothorax, rather flat, narrowest about the middle, wader 



