682 Dr. T. A. Chapiuau on Asijiamctry in 



In Macroglossa the tube is very short and wide ; besides 

 less easily described irregularities, it carries a curved spine, 

 arising on the right side and curving over the dorsum, 

 parallel to the margin. llhopaJoi^sychc anil lihodosoma are 

 not very dissimilar, Enyo, Satafqics, and Aellcqnis incline 

 rather to follow the pattern of HemarU, in which the 

 mdceayus is extremely slender and rather long, and has a 

 spine, continuing the line of the tube from its left margin,^ 

 so that the tube appears to taper to a point and to have 

 the opening on the right side, just where the tapering com- 

 mences. The difficulty of grounding ideas of relationship 

 on similarity of these structures is iikistrated by the very 

 similar structure in S'pMiw' innasto'i, where the tube is long 

 and very slender and ends in a similar point to that in 

 Ilcmaris, it is however on the right side and has two 

 subsidiary processes beside or opposite to it. 



In Bcikyhila {EwpJiorhLv, galii, lincnta) there is a 

 curious valvular arrangement, in connection with a strong 

 armed ridge running down the right margin. 



In the genus Hemaris the slenderness of the /vdcvagus 

 makes it easy to overlook its asymmetrical character, but 

 here the harpes and valves have become involved. 



In Sphinges (broadly) the valves are wide and large and 

 free from any special developments, basally and ventrally 

 however there are, when present, the harpes, consisting on 

 each valve of a rather swollen base which carries a process, 

 that lies just within the margin of the valve, sometimes a 

 thick baton, a short or a very long slender hook more or 

 less curved, etc. ; and nearer the centre of the valve another 

 usually conical process or spine. The latter is very usually 

 absent, it is apparently, hardly, if at all, represented in 

 Hemaris. It possesses, however, the first process as a 

 straight baton somewhat bulbous at the end, or at least one 

 supposes the original Hemaris with the parts symmetrical 

 did so. The first step in asymmetry is for this process to 

 disappear on the left side, it tended next to disappear on 

 the right also, but nieantime the left valve became einargin- 

 ate, and so in Hemaris there arc varying degrees of loss of 

 the batons and emargination of the valves, always far 

 advanced on the left side. 



In Cephonodes, the batons are entirely gone, and a great 

 emargination of the left valve occurs. In the Indian Hylas 

 the two cusps at the margins of the left valve are much alike 

 in structure. An apparently identical insect, from I 



