pciuuin^— sciuRorxEuus volucella. 



m 



Alaska oiul LduiMiniia, Novu Scutiu uikI Culilorniu, uiul frum iimiiy iuternic- 

 (liute localUies. As Hhowii by the subjoined table uf nicnsurcinents, there is 

 a gradual decrease in size from the north suuthward. The avcrnge length 

 of specimens (exclusive of the tail) from Arctic America is about 7.50; of 

 specimens from nenr tlic 40th parnllel, about 85, or a little less, ranging 

 from 7. 10 to 6.50; of specimens from Northern New England, about 5.75, 

 ranging from 6.00 to f 35; of specimens from Southern New England, about 

 5.25,* ranging from 5.50 (o. even 6.00) to 4.50; of specimens from the Gulf 

 States, alxiut 4.75, ranging from 5 20 to 4.30, or about one-third less than 

 the most northern specimens. 



In respect to color, specimens from the same locality sometimes differ 

 in the color of the dorsal surface as much as do the most diverse examples 

 from widely separated localities. There are, however, easily recognized '"cal 

 differences of coloration, especially in respect to the tail; but even here there 

 is a considerable individual (or seasonal?) variation. As a rule, the speci- 

 mens from north of the United States have darker tails than those from south 

 of the parallel of 44°, while the average difference in color between northern 

 and southern specimens is quite marked. 



A series of five specimens from the Red River r>'' the North nearly 

 covers the whole range of variation in color exhibited by the whole series 

 No. 3257 (Red River Settlement) is dark fuscous-brown above, with the tail, 

 especially the distal half, decidedly blackish, and the under parts faintly 

 washed with rasty-fulvous. No. 3717 (same locality, December 10) is soil 

 yellowish-brown above, with the tail mucii less duxky, and the under parts 

 white, with merely the faintest tinge of yellow. No. 3718 (same locality 

 and date) is quite similar, but shows a variation toward No. 3257. No. 11539 

 (Pembina, June 14) is much redder than 3717; the tail is especially brighter, 

 with much less dusky. No. 9083 (Selkirk Settlement) is very light-colored 

 (as light as any from any locality), being pale yellowish-brown above, with 

 only the terminal third of the tail blackish. 



'Maiij of llw New England specimens (rooctly measnted from aleubolic speoimens) are evidently 

 iromatiira. In the ease of the males, the testes are generally abdominal, and the females show no rlgn 

 ofbsTiDg saeklrd yoang. All the males with the tesiea scrotal and all the females with the (rats bearing 

 eridaoce of materoity are of mnoh larger size than the others. All the measurements of northern speci- 

 meoa bare oeeesaarily been taken from s'jins, some of which are evidently overstulTed. Taking, how- 

 •Tsr, only soeb Beasorements as are least nflfeoted by faulty taxidermy, as the length of the feet and the 

 meMarenMita of the head, in oases where the skull is left in the skin (and only from snch specimens are 

 the ammnnsmmta of (he bead given), there Is evidently a very striking, as well as very gradual, deoreaso 

 in size aontfawanl. 



*2 U 



