134 Objects for the Microscope. 



smaller insects, having a stout short labrum and slender sharp 

 maxillae, with which to kill, as well as a thick broad labium 

 (called the tongue), to suck the food. The larva lives in the 

 earth, in sand or manure, or decayed wood. The pupa is 

 brown, bare, with eleven segments, of which the five poste- 

 rior are furnished with a series of little teeth. 



As it is quite impossible to prepare insects so as equally 

 to display all parts, we may find some difference in the 

 slides, even of the same insect. The Leptis I am now look- 

 ing at shows the beautiful eye and tongue, but not the 

 antennae, and yet they are to be observed as indicative of its 

 individuality, for the veining of the wing is, at first sight, 

 so like that of another family (the Stratiomidse) that we 

 might mistake it if we did not read its name in the antennae. 

 They are small, and seated side by side in the middle of the 

 face, four-jointed, the first short and cylindrical, second 

 transverse, third cyathiform, or cup-shaped, and a long fine 

 bristle makes the fourth joint. 



Here we cannot but admire the delicate network of its 

 compound eye : in life it was of a bright green, and the 

 facets numerous and small. The labium, or under-lip, fur- 

 rowed in the centre, and beautifully marked with tracheal 

 vessels, acts also in contracting and dilating the tongue in 

 the act of drinking. The palpi, or feelers and tasters, are 

 remarkably large and hairy, projecting on each side of the 

 tongue. 



The wings are to be the chief lesson ; comparing them 

 with the simply veined wings of the Phora, as an indication 

 of farthest remove in relationship, whilst they also show us 

 that the Leptis is a near cousin to the Tabanus, or Horse- 

 fly, and to all flies whose wing-veins are crowded together 

 near the fore -border ; the costal vein ending at the tip of the 

 wing, the cubital vein deeply forked, and the fore-branch 

 having a small areolet. There is a discal areolet, large, and 

 emitting three veins to the border, and the anal areolet is 

 open. Eight families, comprising many genera and nume- 

 rous species, have wings upon this plan, and are known by 

 the variation in the joints of their antennae. (See head of 

 Tabanus and slide of Pachygaster and of Beris.) 



