[Berliner Entoniolog. Zeitschrift Bd. XLI, Jalirg. 1 896, Heft L] 285 



Notice on the terms tegula, antitegula, 

 squama and alula, as used in Dipterolog-y, 



C H. Osten Sacken. 



When we keep the wing of a Dipteron stretched out perpen- 

 dicularly to the longitudiiial axis of the body, and when we follow 

 its posterior margin towards the root, we meet the axillary ex- 

 cision, foUowed by the alula {lobulus Kirby and Stenhamniar; 

 Afterlappen Schin.) with which the hyaline portion of the posterior 

 margin ends. Beyond the alula there is a more chitinized and 

 nearly opaque membrane, which connects the alula with the corner of 

 the scutellum. This connecting membrane varies very much in 

 its breadth in different groups of Diptera; generally it is expanded 

 into one or two rounded lobes, which were called squamae by most 

 aiithors (squama super ior and inferior, when there are two of 

 them). The designations super ior and inferior are not happily 

 chosen, because they describe the position of the s(iuamae when the 

 wings are folded; when they are expanded, the squamae cease to be 

 superimposed; and it becomes then evident that one of them is 

 fastened to the wing and moves with it, while the other, the true 

 squama, is fastened to the thorax and is stationary. The designation 

 squama superior and inferior was evidently introduced by those 

 who principally studied pinned Diptera. 



Anterior and posterior would have been more appropriate 

 expressions. Whenever the true (posterior) squama is rudimentary 

 (as for instance in the Nemocera), it was considered by describers 

 as non-existing. The anterior squama, fastened to the wing, in such 

 a case, remained without a name, and was generally overlooked, 

 although it aifords very good descriptive characters. I confess myself 

 guilty of this negligence in my writings on Tipulidac, and it is 

 only lately (1892) that I became aware of this Omission, and intro- 

 duced, for the anterior squama, an independent name (antitegula). 



