A NEW SPECIES OF PARAPHELINUS. 45 



It was interesting to find that after ten years the balsam had hardened only for a 

 short distance from the edge. After being detached the specimens were thoroughly 

 soaked in xylol and transferred to spirit, after which they were manipulated in the 

 usual way. 



External Morphology of Paraphelinus, Perk. 



In the following account of Paraphelinus some notes of more than generic appli- 

 cation have probably been included. The value of particular characters, whether 

 tribal, generic, or specific, is at present very imperfectly understood in the Aphelinines. 

 In particular, too little attention has been paid (a) to the clypeus and mouth- pa its, 

 especially the labrum, (b) to the sternal apophyses, and (c) to the general chaetotaxy ; 

 and in respect of these and some other features, I have tried to place the genus on 

 a sounder basis. 



Although the elongate facies, the antennae, and the head, distinguish the group 

 at a glance, it is perhaps worth noting that one of its most striking features — the 

 course and ending of the genal keel — might quite easily arise by an exaggeration of 

 conditions obtaining in other allied genera. In the not very closely related Cocco- 

 phagus group, e.g., in some quite thin-headed forms, the keel is well forward, though 

 the genae are normal. A little further shifting would cause the lower extremity of 

 the keel to fuse with the sides of the clypeus and the condition found in Paraphelinus 

 would result. Similarly the antennae with their distinctive " elbow " and terminal 

 " horn " might result from an inconsiderable modification of the antenna in Aphelinus 

 itself. The cumulative effect of such slight differences however is decided, and 

 (apart from their host attachment) the species showing them form a compact genus. 



The two known males are easily separated, but the females are extremely uniform, 

 presenting differences of a rather critical nature. In discussing the antennae I state 

 that 6 (7) joints are present ; i.e., of these six are obvious, but the first funicular has, 

 I believe, the lamina or disc of the ring joint fused to it basally. With Perkins 

 and Howard I assign the penultimate joint to the fnnicle and consider the last joint 

 to be a solid club ; Girault treats the penultimate as the first of a two-jointed club. 

 In its natural position (seen best in a specimen mounted without pressure in a cell 

 or under a supported cover-slip) the antennal " beak " curves gently outwards and 

 the sense-organ appears in its normal position on the inner aspect. When, however, 

 the antenna is mounted separately, the weight of the cover-slip, without distorting 

 the general shape, brings the surfaces into the same or parallel planes, when the tip 

 of the antenna appears to be decurved, and the sense-organ is dorsal. All the figures 

 of the antenna have been drawn from this position. Besides the usual linear sensoria 

 the club bears two peculiar organs each with a central stouter bristle (?); 

 focussing down a little, these organs seem circular, but when the central bristle is 

 distinct the surrounding rim is vaguer. The head is particularly difficult to examine, 

 owing to the inequalities of surface it presents, and to its liability to collapse during 

 the process of mounting. The chaetotaxy and shape of the clypeus may be made 

 out in shrunken specimens, but notes on the proportions are worthless unless the head 

 is naturally swollen. 



In the thorax noteworthy features are the slight advance of the axillae, 

 structure of the sternopleurae, etc. One peculiar abnormality of the dorsal chaetotaxy 



