TRANSFORMATIONS OF BUFFALO GNATS. 31 



just finished ovipositing. Four others which subsequently laid from 

 89 to 349 eggs while in captivity were also captured. The adults 

 lived after oviposition from 15 minutes to 67| hours, and were dis- 

 sected immediately after death. Their ovaries were found to contain 

 in each case a large quantity of eggs of the round type corresponding 

 to stage 1 (PL I, fig. 1) with the exception of the specimen which 

 lived only 15 minutes after oviposition and in which the eggs within 

 the ovaries were only visible under a high magnification. The ovary 

 of one specimen contained in addition, near the oviduct, a large fully 

 developed egg which had not been deposited. This last-mentioned 

 condition (stage 5, PI. 1, fig. 5) was also found in adults taken 

 engorging upon mammals and killed at the time of capture. 



CONDITION OF THE OVAKIES OF ADULTS TAKEN FEEDING ON MAMMALS. 



In order to demonstrate the relation between the amount of en- 

 gorgement and its apparent effect upon the development of the eggs 

 within the ovaries, the condition of the ovaries is discussed collect- 

 ively with regard to the previous amount of engorgement by adults, 

 irrespective of the dates on which the adults were captured. 



The following symbols are used in description to separate the 

 varying degree: (-(-) Slight and partial engorgement, or about one- 

 fourth the utmost capacity; (-\ — [-) fair engorgement, or one-half the 

 utmost capacity; (-\ — | — |-)well engorged, or three-fourths the utmost 

 capacity; (-| — | — | — \-) complete engorgement, or distension of the ab- 

 domen to its utmost capacity. 



CONDITION OF THE OVARIES OF ADULTS KILLED AT TIME OF CAPTURE. 



Ten adults were taken from time to time engorging on the blood 

 of mules. They were killed at once to obtain data on the condition 

 of the ovaries at the time of engorgement. Two specimens were 

 slightly engorged (-J-) ; in one the ovaries showed a condition corre- 

 sponding to stage 5, each ovary containing about 12 fully developed 

 eggs, the remainder of the ovary being filled with eggs of the round 

 type ; in the other the ovaries contained only eggs of the round type 

 in large quantity (stage 1). One specimen was half engorged 

 (-) — J-) ; its ovaries were in a condition typical of stage 5, being filled 

 with small round eggs and containing in addition 8 large fully de- 

 veloped eggs in a free condition, which seem positively to have been 

 developed at a different period from the rest of the ovaries. One 

 specimen was fairly engorged (-| — | — f-) ; the ovaries contained only 

 eggs of the first stage in large numbers (stage 1). Six specimens 

 were taken fully engorged (-) — | — | — f-) ; all of the ovaries were in a 

 condition typical of stage 1, the eggs being of the small round type, 

 translucent, and in large numbers. 



