TENENT HAIRS 



99 



it, climbing, digging, etc, ; their legs are provided not only with 

 spines and bristles, but with still other appendages, which may be 

 useful, or only ornamental, as secondary sexual char- 

 acters." 



Tenent hairs. --Projecting from the lower surface 

 of the empodium are the numerous " tenent hairs," 

 or holding hairs, which are modified glandular setae 

 swollen at the end and which give out a minute 

 quantity of a clear adhesive fluid (Figs. 108, 109, 

 130, 134). In larval insects, and the adults of certain 

 beetles, Coccidse, Aphidae, and Collembola, which have 

 no empodium, there are one or more of these teneiit 

 hairs present. They enable the insect to adhere to 

 smooth surfaces. 



Striking sexual secondary characters appear in the 

 fore legs of the male Hydrophilus, the insect, as 

 Tuffen West observes, walking on the end of the tibia 

 alone and dragging the tarsus after it. The last tarsal 

 joint is enlarged into the form of an irregular hollow 

 shield. The most completely suctorial feet of insects 

 are those of the anterior pair of Dyticus (Fig. 132). 

 The under side of the three basal joints is fused together and enlarged 

 into a single broad and nearly circular shield, which is convex above 



R 



FIG. 107. End 

 of tibia anil tarsal 

 joints of Anoph- 

 thalmus; t', comb. 



n< 



ch 



Fi<;. 108. Transverse section through a tarsal joint of Telephorus, a beetle : ch, cuticula of the 

 upper side; in, its matrix ; ch', the sole ; m', its matrix : 7i, adhesive hair ; &', tactile hair, supplied 

 with a nerve ('), and arising from a main nerve (it I ; n", ganglion of a tactile hair; 1, section of 

 main trachea, from which arises a branch i/'i; '//'. glands which open into the adhesive hairs, and 

 form the sticky secretion; e, chitinoiis thickening; x, sinew; /;, membrane dividing the hollow 

 space of the tarsal joint into compartments. See p. 111. After Dewitz. 



and fringed with fine branching hairs, and covered beneath with 

 suckers, of which two are exceptionally large ; by this apparatus of 



