32 
Psyche 
[March 
conditions prevail in both English and American examples. 
In both sexes, irregularity exists in the relative length of 
the legs (the third pair always the longest), due chiefly to 
the variability of the first tarsal joint. 
Antenna of the male (Plate 3, fig. 2). — Bipectinate from 
the third or fourth joint. The third joint, sometimes show- 
ing a short pectination, is usually more or less fused with 
the fourth; and the distal joint may be simple or bipectin- 
ate, according to its degree of fusion with the next. The 
longest pectination (balsam mount) measures .52 mm. The 
shaft and dorsum of the pectinations are clothed in ap- 
pressed scales (these and the fine hairs of the pectinations 
not shown in the figure) . The apparent number of antennal 
joints is usually 20, but these by fusion may be reduced to 
18 or 19, and in one instance we were able to count 21 
joints. 
Antenna of female (Plate 3, fig. 7 ). — Simple, bead-like, 
consisting of 13 joints of irregular size. Occasionally 14 
joints may be detected. 
Abdominal plates and genitalia of male (Plate 3, figs. 3 
and 4).-— By direct comparison we detect no essential dif- 
ferences in these structures, between our Massachusetts in- 
sects and casta as identified by English entomologists. 
Ovipositor of female (Plate 3, fig. 8). — The ovipositor is 
capable of extrusion until it equals the entire length of the 
remainder of the insect. Balsam mounts of the female 
abdomen show prominently three sets (of 2 each) of hair- 
like black rods, which function in the telescopic mechanism. 
Mounts from English casta show these rods to be identical 
in number, shape, and position with those of Massachusetts 
insects; and this apparent identity extends to relative 
length of the three sets, with such exactness that specific 
identity of the insects seems assured. Preparations by 
identical technique, drawn and measured at the same mag- 
nification, for the three sets of rods give these ratios of 
length : 
5 English casta, from the 
Chapman and Burrows collections 36 : 48 : 147 
3 Massachusetts casta 36 : 50 : 147 
