( cxxxrii ) 



I have already figured in our Transactions the male arma- 

 ture of Cossus cossus, as also of Duomttus leuconota, but it 

 may be well to consider another, and I will, therefore, take 

 one widely removed geographically. 



Langsdorfia frankii. 



The structure of the tegumen in vertical sections is similar 

 but it is decidedly smaller, and is without the pendant arms ; 

 the harpagoncs are not bridged over but are large, and at the 

 rear of the upper margin they have a peculiar organ almost 

 like a pair of callipers in shape, only the lower half is by no 

 means so long as the upper ; it consists of two horn-like 

 extensions, the upper one curved, the lower one more or less 

 straight, flexibly articulated at the base and attached to the 

 margin of the harpago — the harj)agones themselves are 

 beautifully edged with long hair-like fringes; the sedceaga} 

 trough is prominent and the sedosagus somewhat similar to 

 that of Cossus. The cingula differs from both Cossus and 

 Duomitus in that it is developed into a complete collar. In 

 addition to this there is a peculiar structure on the dorsum 

 of the eighth tergite, consisting of a dorsal saddle with a 

 deeply curved and strong hook, which apparently may hook 

 into the tegumen. 



From my description it will be seen that the genitalia o 

 Langsdorfia form a distinct advance on those of Cossus or 

 Duomitus, whilst at the same time they are essentially Cossid 

 in character, the reduced tegumen, however, and the complete 

 cingula show a decided upward development. 



The Zygaenidae are another very primitive group, and 

 judging from the male organs I am inclined to think 

 that Adscita as represented by statices or geryon (which are 

 thoroughly representative in structural detail) is more 

 primitive than Zygaena, but Heterusia, whilst quite primitive 

 in its tergite, is highly specialised in the sternite organs; 

 this, however, is perhaps what might have been expected — 

 i. e. some specialisation — from other aspects of the genus. 



Adscita geryon, Hb., 



has the tegumen consisting of a very narrow dorsal bridge, 

 from which is emitted a strong hook curved downwards ; 



