588 



THE MICROSCOPE. 



extensor muscles are attached to both ungues and the 

 flaps ; the flaps, corrugated or arranged on the ridge and 

 furrow plan, are in some cases perfectly smooth on 

 their superior surface, in others this surface is covered 

 with minute scale-like hairs. The thickness of the flaps 

 on the Blow-fly does not exceed the l-2000th of an inch 

 at the margin ; thence they increase in thickness towards 

 the point of attachment. Projecting from their inferior 

 surface are the organs which have been termed ' hairs,' 

 ' hair-like appendages/ ' trumpet-shaped hairs,' &c. That 



these are the immediate 

 agents in holding is now 

 admitted by most obser- 

 vers, and it will be con- 



venient to term them 

 '"tenent" hairs,' in allu- 

 sion to their office. Plate 

 VI. No. 140, the under 

 surface of left forefoot of 

 Musca Vomitoria, is shown 

 with tenent-hairs ; a and b 

 are more magnified hairs, 

 a from below, b from the 



Gside. No. 142 is the left 

 ' forefoot of Amara commu- 



nity showing under surface 

 and form of tenent appen- 

 dages, one of which is seen 

 more magnified at a. No. 143, under surface of left forefoot, 

 Ephydra riparia. This fly is met with sometimes in im- 

 mense numbers on the water in salt marshes ; it has no 

 power of climbing on glass, which is explained by the 

 structure of the tenent-hairs : the central tactile organ is 

 also very peculiar, the whole acting as a float, one to each 

 foot, to enable the fly to rest on the surface of the water ; a 

 is one of the external hairs. No. 135, under surface of left 

 forefoot of Cassida viridis (Tortoise-beetle), showing the 

 bifurcate tenent appendages, one of which is given at a 

 more magnified. These, in the ground-beetles, are met 

 with only in the males, and are used for sexual purposes,. 

 The delicacy of the structure of these hairs in the fly, the 



■--- i^U-^' 



Fig. 265. — Sucker on the leg of a Water- 

 beetle. (The dot in circle shows the 

 object natural size.) 



