292 MR, B. F. CUMMINGS ON LICE 



spiracle lies on the inner margin of each plemite, about halfway 

 along its length. Tergites are present in the form of circular or 

 oval plates, two on each segment, and each tergite is just on the 

 inside of, but separated by a space from, the j^leurite. In the 

 adult this space is filled in, and the tergite and pleurite unite. 



Chcetotaxy.- — Abdomen : This differs but little from that of the 

 adult female. But there are apparently some interesting differ- 

 ences from Stage I. (compare the metanotum in text-figs. 21 & 

 22). There are fewer hairs in the mid-dorsal region of each 

 segment, and the cha^totaxy around the end of the abdomen' and 

 the genital opening differs considerably, of course, from the adults, 

 in which the sexual organs are matured. 



Genus Rhopaloceras Taschenberg. 



Rhopaloceeas stylifer Mtzsch (10, p. 200). (Text-figs. 28, 

 24.) 



1 c5' • Host not given ; probably f I'om Meleagris gallopavo 

 Linn. 



Male Cojndatory Ajiparatus (text-fig. 23). — For the purposes of 

 the folloAving description I have been able to make use of speci- 

 mens of this common Turkey parasite, kindly placed at my 

 disposal by the Rev. Jas. Watei'ston, B.Sc. 



The apparatus in this remarkable-looking insect presents 

 features of great interest, inasmuch as it is reduced to a very 

 small size (although in no sense atrophied), in correspondence no 

 doubt with the fact that the terminal segments of the abdomen 

 have become modified so as to take part in the function of 

 copulation. Similar adaptation of the end of the abdomen to 

 the function of copulation is not lare in Mallophaga. Based 

 2}late : Long and narrow, mai-gins slightly thicker than the 

 median area ; the anterior end a little broader and thinner. 

 Best of the Ap2)aratus : This is so highly modified that the 

 attempt here made to bring it into line with the parts in other 

 Mallophaga is only partial and tentative. Parameres as such ai'e 

 absent. Instead, articulating with the basal plate is a small 

 trowel-shaped plate Avitli the concave side uppermost. Along 

 the lateral margins (dorsal surface) of the distal half of this 

 plate there are on each side seven minute directive hairs with 

 large alveoli. Contained within the hollow formed by the 

 trowel-shaped plate, and coiling upwards and backwards so as 

 to resemble a crook, lies the penis (or a pseudo-penis ?). This 

 crook-shaped piece at its base is set in a stout horseshoe-shaped 

 piece of dense chitin, the two arms of the horseshoe being- 

 directed towai-ds the basal plate. The parts are pei'haps a 

 modification of those of G. gigas (see text-fig. 18), the jiarameres 

 having coalesced. {Cf. 4, fig. 143.) 



Terminal Segments of the Abdomen of the Male (text-fig. 24). 

 Dorsal surface: The 7th tergite is a narrow transverse band which, 



