146 Annals Entomological Society of America [Vol. VIII, 
membracid. The experience of that author, however, in rearing 
the nymphs of Entylia sinuata, in which species the molting was 
not successfully accomplished in the laboratory without the 
presence of ants, has not been experienced in the rearing of 
Thelia bimaculata, since this latter insect has molted repeatedly 
while in the cages in the insectary without the attendance of 
ants. The feeding of this membracid, likewise, has not seemed 
to be affected in the least by the absence or presence of these 
usual attendants. 
Hosts. 
Robinia pseudacacia L. seems to be the only host supporting 
Thelia bimaculata in this locality. Specimens have never been 
taken on any other tree although in general collecting for Mem- 
bracide practically all of the local flora has been examined. 
Likewise, no evidences of eggs or nymphs have ever been found 
except on this one host. Neither have specimens of this species 
been collected in the grass or weeds or by sweeping and it seems 
evident that the entire life cycle of the insect is spent on the 
locust. As has been stated, the migration of this form seems to 
be limited and the insects appear year after year in a given 
group of trees while others nearby are not infested. 
ENEMIES. 
Parasitism is common in the eggs but none of the parasites 
have been identified in the course of this study. Many eggs fail 
to mature and are found to be punctured and blackened. The 
bodies of both nymphs and adults, also, often contain larva— 
apparently hymenopterous—but none of these have thus far 
been successfully reared although several attempts have been 
made to work out this phase of the subject. Matausch has 
recorded parasitism in this speciest which destroyed the sexual 
organs but was not able to rear the parasites. 
The larger Asilids occasionally carry off a membracid and in 
one instance a toad was found at the foot of a tree busily engaged 
in trying to secure the nymphs. In this case the operation 
seemed to be fraught with some difficulties on account of the 
tenacity with which the membracids held to their host and on 
account of their sheltered position in the cracks of the bark, 
+ Matausch, Ignaz. The effects of parasitic castration in Membracide. Jour. 
N. Y. Ent. Soc., Sept., 1911. Vol. XIX: No. 8. 194-196 p. 
