( 320 ) 



tliem, are placed at the ventral angle of the hinder portion of the head immediately 

 behind the antennal groove. The bristles on the posterior j)ortiou of the head 

 are numerous. 



Thorax. — The pronotal comb consists of thirty-six teeth. The mesonotum 

 bears on each side, before the apex, two slender teeth. On the metathorax 

 there is a " comb " (fig. 8, C), which is not homologous to the combs found 

 on other sjiecies of Si])honaptera, being a development from the snbajiical row 

 of long bristles found in these insects. This is clearly demonstrated by the 

 thoracic and abdominal combs of the i)resent species gradually merging into the 

 ordinary bristles of that series, as is shown in the figure. The lateral teeth of 

 this " false " comb do not stand at the edges of the segments ; the shorter and 

 more central teeth, however, have acquired this position in consequence of the 

 apical margins of the segments being dorsally sinuate. The teeth of the meta- 

 thoracic comb are much less modified than those comjiositig the combs of the 

 first four abdominal tergites. The epimerum of the metathorax bears a number 

 of bristles. One of these is situated behind the stigma. Three more are placed 

 at the hinder edge, of which the up])er two are nearly of the same length, while 

 the third is shorter and thinner. In addition to these, there are seven or eight 

 more bristles, as shown in the figure. 



Abdomen. — On the first seven tergites, combs similar to that on the meta- 

 thorax. are jiresent. The modification of the bristles into a comb-like structure is 

 least advanced on the sixth and seventh tergites, where only two to four bristles 

 have become shortened and thickened. These bristles do not stand exactly at the 

 edge of the segments, the small siuus not being sufficiently deep. The number 

 of teeth in the abdominal false combs varies considerably in individuals. The 

 comb on the first tergite consists of from ton to twelve teeth. The number of 

 teeth present in the abdominal combs gradually decreases. The first three tergites 

 bear two irregular series of hairs, in addition to the posterior row of long bristles ; 

 the remaining tergites, however, bear only one row of short hairs, besides the 

 long ones of the posterior row. The seventh tergite in both sexes bears one long 

 apical bristle on each side, situated on a cone. 



The third, fourtli, fifth and sixth sternites of the male bear from three to four 

 bristles on each side, while the seventh segment bears a row of from seven to 

 nine. In the /etnale these hairs are considerably longer, and occasionally more 

 numerous. 



Legs. — Tiie posterior femur bears four subapical bristles, two of which are 

 lateral and two subventral. There are three pairs of bristles on the ventral side 

 near the base. The hindtibia is clothed on the outer side with two rows of hairs, 

 and bears, in addition, a number of shorter ones situated more ventrally. 



Modified Segments. — The eighth tergite of the Male is sinuate below the 

 stigma, and produced upwards behind this sinus into a broad lobe (fig. 9). This 

 lobe bears three long bristles, and there are in addition a number of marginal 

 hairs above these bristles. The ventral distal edge of the segment is minutely 

 serrate. The eighth sternite (fig. 11) is somewhat sole-shajjed, and bears numerous 

 short hairs. On the inner side there are brushes of long hairs similar to the brushes 

 found in the following insect. Of the clasping organs the broad process P (fig. 10) 

 is very conspicuous on account of the six or seven long bristles situated in a row 

 at its ajiex. The finger (F) is square, and its ujiper jiroximal corner is produced 

 into a short conical process, bearing a short spine near the tip. 



