16 BULLETIN 766, U. 8. DEPARTMENT OF AGRICULTURE. 
The pupa stage of Compsilura is passed in two ways. In the 
field, puparia will be found both in the crevices of the bark and in the 
webs of prepupal brown-tail moth larve or “spin-ups.” They will 
also be found about 1 inch beneath the surface of the soil at the 
base of trees. The average length of the pupa stage in the soil is 
from two to four-days greater than above ground. 
ADULT STAGE. 
The length of the adult stage under laboratory conditions varies 
with the temperature and methods of handling. The methods of 
handling have been previously mentioned. The average length of 
the adult stage of Compsilura is shown in Table IV. 
TasLeE [V.—Average length of adult stage of Compsilura concinnata, Melrose 
Highlands, Mass, 1916. 
22 days for 35 mated males in glass-covered trays. 
18 days for 35 mated females in glass-covered trays. 
13.5 days for 22 unmated males in glass-covered trays. 
4.5 days for 22 unmated females in glass-covered trays. 
GESTATION. 
The period of gestation varies with the temperature, an increase in 
temperature tending to shorten the period. A new supply of hosts 
was added every two days and close watch for the emergence of Comp- 
silura larvee was maintained. The time required for the period of 
gestation was reckoned from the time of mating to the time the 
adults and hosts were separated; then, to get accurately the length of 
the larva stage, each maggot was isolated as it emerged from the host 
and the larva stage was reckoned from the end of the period of 
gestation. (See Table V.) 
TaBLeE V.—Gestation period of Compsilura concinnata: Single females in each 
experiment, Melrose Highlands, Mass., 1916. 
Age off Bonne BOCTIEE Gesta- 
Date experiment Pe a Sallie P length of| Numberand stage Tost fife 
began. SCOR Tal Se Ore larva ofhosts. ; : Higa 
lation. larve Stace period. 
secured. Be. 
Days. Days. Days. 
lye osee sere 1 3 9.5 | 30, fourth stage....) Brown-tail moth larve. - 4.5 
ee Ser 2 13 7.42 | 70, fourth stage....|...-- dossiers 5 
IGS. 32 See: 2 8 7.23 | 60, fourth stage.-..|.--.- GOs soho eee 3 
Sls Fs eeee 2 1 10 70, fourth stage-..--|..--- GOjess eueee eee 6 
Average:=s|- Shi ncace les. 2S Seg Oaks Se cig. || 538 SS Ee ree Bs Ree eee 4.5 
PARTHENOGENESIS. 
Since it was thought that Compsilura might, at times, be par- 
thenogenetic, a series of experiments was conducted to determine 
whether this is the case. In each case 5 unfertilized females were 
