292 Annals Entomological Society of America  [Vol. XIV, 
four hours to six days. Prior to removing the specimen from 
the solution the ovipositor was distended by lightly placing 
a blunt dissecting needle on the exposed portion of the ninth 
segment and with forceps or another needle gradually drawing 
away the excised portion of the abdomen from the point of 
attachment. This pulled out the ovipositor in a telescopic 
manner and allowed it a better opportunity of clearing. After 
thoroughly washing in water the ovipositors were placed in 50 
per cent alcohol and run through the successive grades to 70 
per cent, at which they were preserved for drawing and examina- 
tion under the low powers of the microscope. For examination 
under high power, slides were prepared by continuing the 
dehydration of the ovipositors through successive grades to 
absolute alcohol, thence passed through xylene, and finally 
mounted in 50 per cent xylene, 50 per cent Canada balsam 
mixture, directly under a coverslip and within an xylonite ring. 
Drawings were made from the preserved specimens and 
prepared slides with the aid of a micrometer eye piece and 
squared graph’ paper. No attempt was made to show the 
relative sizes of the ovipositors, but only the proportional 
composition of each. 
GENERAL MORPHOLOGY OF THE OVIPOSITOR. 
The ovipositor represents the terminal segments of the 
abdomen, namely six to nine. They are modified for the 
purpose of conveying the egg to its destination during ovi- 
position. On account of this peculiar function the abdominal 
sclerites and membranes have become altered so that they no 
longer resemble in general appearance the anterior segments, 
namely, numbers two to five, but are diminished in size to form 
a tubular structure, neatly telescoped within itself and which, 
when at rest, come to lie within the fifth abdominal segment. 
Berlese (Rivista de Patologie Vegetale, 1902, ix:345-354) in 
his observations on the copulation of the house fly, claims that 
the ovipositor also functions as the active organ in securing 
fertilization, the male organs being the meanwhile conspicuously 
inactive. Since the structure of the ovipositor and the male 
genitalia of Musca domestica Linn., and the following Anth- 
omyian flies are essentially alike, especially with regards 
vestiture, it 1s not improbable that an additional function 
exists here also. 
