PSYCHE. 



A PECULIAR CASE OF PARASITISM WITH HEMEROCAMPA 



LEUCOSTIGMA SMITH & ABBOT, WITH DESCRIPTION OF 



A NEW GENUS AND SPECIES OF PTEROMALIDAE. 



BY A. ARSENE GIRAULT, URBANA, ILLINOIS. 



Two similar cases of parasitism, one of which is new to this Host, were found to 

 occur with a lot of parasitized specimens of the fall generation of 1907, collected 

 from shade trees at Chicago, Illinois, by Mr. H. E. Hodgkiss then connected with 

 this office. The specimens consisted mostly of dead male and female pupae in their 

 cocoons, a few egg-masses of the moth, and many cocoon-clusters of Pimpla inquisi- 

 tor Say, the whole evidently obtained from shade trees in the various parks of the 

 city. They Avere in good condition in the spring of 1908, having passed the winter 

 in the cold insectary, and on April 15th, 1908, the Pimpla began to emerge in num- 

 bers ; hyperparasitism in this case occurring very rarely or not at all, though in some 

 of the Pimpla cocoons fragments of obvious hyperparasitic pteromalines were found. 

 In this lot, the parasitism of Pimpla was normal in every way, but in passing, I desire 

 to record the fact, previously recorded by Howard (1897, pp. 12-13), that in a lot 

 of the same host parasitized by this species kindly collected at Chicago May 19th, 

 1908, by Mr. J. J. Davis of this office, and consisting of specimens of the fall genera- 

 tion of 1907, four cases of abnormal pupation were found, in that the larva had con- 

 structed the cocoon within the host instead of without as is normal. This was found 

 in the instance of four female host pupae, in the first of which were four of the Pimpla 

 cocoons, in the second, five of the Pimpla cocoons, in the third, two, and in the fourth 

 and last, three of the cocoons of the parasite. In still another instance a single 

 cocoon of the Pimpla, apparently inquisiior, was found within the body of the full- 

 grown host larva. These Pimplas had all emerged, excepting one or two which were 

 found as adults, dead in their cocoons. 



On April 19th, it was noticed that a pteromalid was emerging and upon investi- 

 gation, the particular host pupa infested with this species was isolated and after- 

 wards dissected, before further emergence occurred. The host proved to be a female 

 pupa in its cocoon, and dissection revealed a compact mass of eggs which had devel- 

 oped in the ovaries of the far advanced pupa, and packed in between these, singly, 

 the living adults of this parasite; a number of meconial discharges were also found. 

 From the single host, 4 males and 15 females were obtained, including the pair which 



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