98 • ARNOLD W. COOPER. 



I have not seen any note mentioning the extreme elasticity 

 of the spermatophores which the following incident exem- 

 plifies. Having" mounted a specimen in damar after the usual 

 fixation in perchloride of mercury and acetic acid, passing 

 through absolute alcohol after staining, and clearing in oil of 

 cloves, a Siight accideut happened to the mount. In trying 

 to re-arrange the specimen with a fine needle, one of the 

 spermatophores attached to the vulva became detached and 

 stretched to nearly twice its normal length, the two ends 

 being connected by a thread-like portion only ; in less than 

 an hour afterwards it had assumed nearly its former shape 

 and proportions. 



Description: 



Body. 



Total length of female r8-l"9 mm. Male somewhat smaller. 



Male. — Thoracic segments five, the anterior segment 

 being partially fused with the head, the last thoracic segment 

 being rounded along the posterior edge. Abdomen five 

 segments. F urea symmetrical, each fork with five jjlumous 

 bristles (fig. 2). Genital aperture at the anterior end of the 

 second abdominal segment. No median dorsal spine. 



Female similar to the male, except that the last thoracic 

 seg-ment is drawn out into a rio-ht and leftbackwardlv directed 

 flange (fig. 3). Abdomen consists of two segments, the 

 vulva being in the middle of the first. Furca symmetrical, 

 each fork bearing five short swollen plumous setss. No 

 median dorsal spine. 



Cephalic Appendages. 



Antennas 1, Male. — The right antenna consists of twenty- 

 three joints (fig. 4i, the terminal prehensile portion having four 

 joints, the first of these (twentieth joint) with well-developed 

 terminal hinges; joints fifteenth to nineteenth greatly swollen; 

 a hyaline membrane extends along the inner side of the 

 eighteenth, nineteenth, and twentieth joints. 



