) 



139 



to whether the remarkably lar^e terminal joint which I find in the specimen of 



H. ravilla.is constant,— whether, in short, it may not be sexual. In this same specimen 

 the penultimate sesj^ment of the al)domen is truncate or most indistinctly emarginate, 

 and the truncated poition is broader than in the English specimens, which I regard as 

 females of H. angusticollis. In other respects, I can discover no differences between 

 the H. angusticollis and the H. ravilla." 



Mr. Waterhouse then communicated the following note, and exhibited (on the 

 part of his son, Mr. Charles Waterhouse) a series of specimens of a species of Homa- 

 lota, closely resembling H. analis in its general characters, but which will possibly 

 prove a distinct species: — 



" The specimens were collected recently in the Hammersmith Marshes, in company 

 with H. analis, and my attention was first directed to them through the uniform dark 

 (nearly black) colouring of the body and anlennffi. Upon examination, I find that 

 the dark insects differ from H. analis in their sexual characters, the male having 

 a very much deeper notch in the upper plate of the penultimate abdominal segment 

 than in the corresponding sex of H. analis, whilst the female has the plate 

 in question truncated at the apex. After the examination of a very large number 

 of specimens of H. analis, I have not been able to detect any decided distinctions in 

 the sexes through the structure of the penultimate abdominal segment; in all it has a 

 largish notch at the extremity in the form of an obtuse-angled triangle; in some the 

 notch is slightly deeper than in others, but there are individuals presenting inter- 

 mediate conditions. In the penultimate abdominal segment of the darker-coloured 

 insect, the sinus of the upper plate has its depth slightly exceeding its width ; the 

 sides are subparallel, diverging but indistinctly, and the innermost half is nearly 

 semicircular, or we may compare the sinus to the outline of a bluntly terminated cone. 

 The edges of the segment bordering the sinus are margined, — i.e. there is a delicate 

 impressed line immediately within the margin. In H. analis the triangular notch 

 does not show a corresj)onding impressed line: here the plate is slightly arched, but 

 in the transverse direction only ; whilst in the deeply notched segment of the other 

 insect the lateral portions are curved downwards. The apex of this segment is tinted 

 with piceous in both sexes, but I have seen no specimens in which the entire segment 

 is testaceous, as is generally the case in H. analis. The antennae are dusky, often to 

 the base, but sometimes the two basal joints show a dusky testaceous tint in parts, 

 especially on the under side and at the base." 



With respect to this communica-tion, Mr. Waterhouse made the following 

 remarks : — 



" The Homalota soror of Kraatz (Nat. der Ins. Deutschl. p. 257), we are informed, 

 is very closely allied to H. analis, but is distinguished by the antennae being darker 

 and a little more incrassated towards the apex; by the palpi being pitchy brown; the 

 thorax and elytra blackish ; the abdomen almost as thickly, but much more finely punc- 

 tured, and uniformly black. The male has, in the upper plate of the penidtimate abdomi- 

 nal segment, a still larger triangular notch,* the margins of the plate on either side of 



* "Noch weiter dreieckig ausgeschnitten." 1 am not sure that I have rendered 

 this sentence accurately. Both H. analis and H. soror, according to Dr. Kraatz, have 

 a triangular notch or emargination to the abdominal segment in the male, and, as I 

 understand the matter, the segment is still more notched in the latter species than in 

 the former; the term " weiier " cannot be translated simply as "deeper," nor as 

 " wider," but its sense would be conveyed by the two latter terms combined. 



