1922 ] Hymenopterous Genus Harpagocryptus and its Allies. 107 
on the basis of the similarity of the genitalia of the .male and the 
number of antennal joints in the two sexes which is the same as 
that prevailing in Rhopalosoma and most aculeate Hymenoptera. 
There is also a curious similarity in the habits of Rhopalosoma and 
Harpagocryptus. Hood (’13) has shown that the larva of the 
former lives as an external parasite on the jumping tree cricket, 
Orocharis, while Bridwell’s Harpagocryptus was reared from an 
Australian cricket of the family Trigonidiidse on which the larva 
forms a sac like that of certain Dryinidse. 1 This habit would, 
however, not give any reason to associate Harpagocryptus with 
Rhopalosoma rather than with the Drynidse. 
I am unable to reconcile the differences between Rhopal- 
osoma and the genera here discussed sufficiently to assign them 
to the same family. The head in both sexes of Rhopalosoma is 
thin and strongly transverse, the eyes and ocelli very large and 
the front is not produced anteriorly. The thorax has the pro- 
notum very short and collar-like and absolutely different from 
that of Algoa, et al. The propodeum is elongate-oval, not 
truncate nor sharply declivous behind; the abdomen has an 
extremely long petiole; the femora are only slightly thickened 
and the middle coxae are approximate (widely separated by the 
mesosternum in Algoa). Such divergence, particularly in the 
form of the prothorax, head and propodeum is certainly of great 
importance, although the reduction of the eyes, mesothorax and 
scutellum is usually encountered in wingless or subapterous 
Hymenoptera. 
Ampulicimorpha Ashmead, referred by him to the Embo- 
leminae does not show any great similarity to Algoa except in 
the general form of the head and thorax and the external male 
genitalia which resemble those of Olixon as described by Kieffer. 
On the other hand, the peculiar genus Sierolomorpha (placed by 
Ashmead (’03) in the family Cosilidae), resembles Algoa quite 
closely in abdominal structure, in the general form of the thorax 
and head, thickened legs and antennae (cfl3-jointed, $ 12 jointed) 1 . 
: This insect is evidently the undescribed Embolemid mentioned by Perkins ’05 (footnote, 
p. 27) as having been reared from “small cricketes of the genus Trogonidium or allied forms.” 
tAshmead knew only the male, but several years later (Brues ’05) the present writer found 
the female of this interesting insect). 
