18 BULLETIN 766, U..S. DEPARTMENT OF AGRICULTURE. 
after copulation, as records show that this occurs within 26 minutes 
after coition has been completed. 
The host larva will be attacked in almost any portion of the body, 
as larviposition was attempted on the head capsule, the middle part 
of the body, and the posterior segments. Although the middle por- 
tion seems to be preferred, this may be due to the host’s inability to 
disturb the parasite as easily in this portion as it does on either the | 
anterior or posterior end. 
ACTION ON HOSTS OTHER THAN THE GIPSY AND BROWN-TAIL MOTHS. 
In working out the life history of Compsilura various hosts were 
used, all, with one exception, being indigenous to this country. Six- 
teen native species were utilized, and while Compsilura had been 
reared from most of these, attempts at reproduction in the laboratory 
failed on all but four. A matter of interest in connection with repro- 
duction on Callosamia promethea and Bombyx mori, which had been 
reared parasite-free beneath screen, was the high percentage of super- 
parasitism. This was particularly true of Bombyx mori, in several 
instances as many as 10 Compsilura puparia being secured from a 
single host; and of Hemerocampa leucostigma, it being a very com- 
mon occurrence for from 3 to 4 Compsilura puparia to be reared 
from one host. In Table VI are given the results of reproduction 
upon these three hosts. 
TABLE VI.—Development of Compsilura concinnata in various hosts, Melrose 
Highlands, AMass., 1916. 
Age of Proportion 
flies {Number| Average|Number| 7. ah ofsexes. 
WAL when jofComp-| length | of pupa- Ofnt Number and stage Tact 
7806 | experi- | silura | oflarva| riase- | ¢,DOD ofhost. OSS 
ment | larve. | Stage. | cured. ASC: Mal Fe- 
began. &-| male. 
Days. Days. Days. ; 
July 19 3 0 14.76 26 12 19 6 | 50, third! and} H. leuco- 
fourthstages. stigma. 
15 18 5) 17. 20 3 17.33 1 2 | 15, third stage. -_..| C. promethea. 
18 2 23:-| 22.27 | 17} 16.25 8 9 |. 25, third and Do. 
fourth stages. 
19 2 5 19 5 15. 80 3 2 | 25, fourth stage. -. Do. 
19 3 59 15. 60 30 11. €0 17 13 | 35, fourthstage...| Bombyx mori. 
24 4 60 19S OS) Seka. SE aera ee a eee eae ee 50, fourthstage. -. Do. 
1 These stages refer to each molt of the host larva. 
Pontia rapae is a splendid intermediate host for Compsilura, this 
pest being found in New England wherever cabbage is grown, and 
because of the overlapping of its broods, which makes it possible to 
find nearly all stages of larvee in the field from spring until winter, 
Compsilura is assured of at least one host upon which to perpetuate 
itself. Fortunately, however, Compsilura is not compelled to rely 
solely upon Pontia rapae for existence, as a glance at the native host 
list will show. 
LD abe et ty me th aa lll A 
