19120 1G9 



the male ; the costa about reaches the middle of the wiug, and the 1st 

 costal division is not more than half as long again as the 2nd, whereas 

 in the male it is twice as long. 



Fungivora. Mr. Collin has bred it from a tree fungus, so that its 

 name is now amply justified. 



Infrajposita. A female (this sex was unknown at the time of 

 introducing the species) was taken at the Middle Park Pool, 4/8/09. 

 It has the same characteristic frontal chsetotaxy as the male. 



. Cilipes. Brues, I find, described an Aphiocheeta cilipes in 1907. 

 Another name must therefore be given the present species, and that of 

 decipiens would seem not inappropriate, since not only has a mistake of 

 nomenclature been made, but a still more serious error has been 

 committed in giving it an iitterly wrong female. In spite of the 

 commonness of the male much difficulty was experienced in discovering 

 an appropriate partner for it, and even after I thought that this was 

 done the selection was felt to be far from satisfactory. Nor can this 

 be wondered at, for the search was made among the species with two 

 scutellar bristles, whilst all the while the creature so badly wanted was 

 amongst the four-bristled kind. The discovery of the mistake we owe 

 to the capture by Mr. Jenkinson at Cambridge of a pair of insects in 

 cop., the male of which was typical decipiens, and the female apparently 

 a small and weak riificornis. So close is the resemblance to ruficornis 

 that there can be little doubt that it is mixed up with that species in 

 most of our collections. It may, however, be distinguished with a little 

 care. Besides being a smaller and less robust insect, the costal fringe 

 is somewhat longer, the 1st costal division also a little longer and the 

 tibial cilia weaker, but a far more satisfactory character is the group of 

 large bristles on the 2nd abdominal segment. In ruficornis they are 

 numerous (quite a bunch of them) and placed upon a lateral prominence 

 of the segment, but in decipiens they ai-e not more than four at the 

 outside, and there is no prominence, the outHue of the segment being 

 flush with that of the segment on either side of it. Mr. Collin points 

 out that in the sexes of both species there is an extra bristle on the 

 thorax, situated out on the disc about midway between the postalar 

 bristle and the dorso-central one. Decipiens will have, then, to be 

 moved from its present position in the table to Section B, where it wall 

 come next to ruficornis. What, it will be asked, are the females which 

 have been doing duty for it ? Scutellaris I am now convinced. They 

 had been picked out because of their proportionately long 2nd and 

 3rd costal divisions, and in the female of this species, as in a few 

 others, these divisions seem to be variable. 



