302 Mr. W. Wesclie's Notes on the valve of 



1901 the Ortalidte, Trypeticte and Loncljasidse follow each 

 other, but the horny telescopic ovipositor of the females 

 and the remarkable development of the Muscid form of 

 the male genitalia show that the differences between the 

 three sections are only generic, and that they form one 

 natural family. This opinion is strengthened by the 

 character of the trophi, which is fairly constant through 

 the group. In the labiums of the Ortalids Seo'ptera vibrans, 

 L., and Fteo^opiectria nigrina, Mg., and the Trypetid 

 Aeidia lyelinidis, F., are similar chitinous paired jDrocesses, 

 which are peculiar and striking. This shows a very close 

 relationship, and proves that a classification which places 

 the two first insects in one family and the third in another, 

 cannot be a natural one. 



Tlic ovipositor. Three types are met with in Diptera, (A) 

 the telescopic or protrusile, (B) the non-telescopic, and (E) 

 the styliform. The telescopic may be subdivided into (C) 

 those with a framework of chitinous rods and (D) those 

 without. The B type is undoubtedly the oldest and seems 

 nearly universal in the Nematocera. A and B are both 

 represented in the Muscidfc, but B is far oftener met with 

 in the Acalyptrates. C seems confined to the Muscidas, 

 but examples of D may be met with in a few Syrphida^, 

 and in the Dolichopodias, Phoridte and Chloropoda^. In 

 some Phoridai the ovipositor has a lever to extend it, 

 somewhat similar in shape to a process found in the non- 

 telescopic ovipositor of the Simulid«, and whose homolouge 

 appears to exist in a different form in the Ghironomyidaj. 



E. The styliform is found in the peculiar organ of the 

 PipunculidiB, but there are one or two aberrant forms such 

 as Phorocera serriventons, Rnd., which I have come across 

 in the Muscidre, which might come under this head, but 

 are really parallel developments. The types may be 

 arranged in a Phylogenetic scheme placed in the order of 

 hypothetical evolution, beginning with the oldest. 



B. Non-telescopic. 



E. Non-telescopic chitinised forms as in Pipunculus. 

 D. Telescopic tvitliout rods other than a single lever. 

 C (}). Telescopic with many rods.^ 



* There are contained in the abdomen, parts of the female 

 genitalia that strangely enough have characters. These are the 

 receptacula seminis ; they vary in number from one to four, have 

 scul})turing on the cases, and may liave characteristic shapes in certain 

 genera, as in Falhqdera., but their differences are mostly specific. 



