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 
Xe?ios (Xe'nos), which infest wasps of the genus Polistes( Po¬ 
lishes). 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,^), 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 RHIN0MACERID,E (Rhin-o-ma. 
Fig. 720. cer'i-dee) 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, wider 
