114 THE ENTOMOLOGIST. 



short steps, the femora being almost horizontal. They move 

 very rapidly, but rarely sustain the effort long— the opposite legs 

 are moved alternately (see p. 112). They seem, however, to 

 have very feeble adherent powers ; if placed on a piece of paper 

 or bit of rough cork and allowed to run about, they always tumble 

 off immediately when the cork or paper is gently inverted, and 

 they are apparently unable to mount a perpendicular glass sur- 

 face. The macropterous form is rather smaller than the apterous, 

 and moves with a somewhat greater rapidity. 



The condition of the pubescence with which these insects are 

 clothed, and of the various longer hairs on the legs, antennae, &c, 

 their smoothness and their freedom from all kinds of extraneous 

 matter, are of prime necessity, and consequently a very large 

 portion of their energies is directed to that end. The cleansing 

 is performed entirely by means of the legs, and may be described 

 as a "dry-wash." The antennae receive especial attention -these 

 are clothed with short, fine hairs, directed forwards from their 

 base ; the Hydroessa deals with each separately, bringing its 

 anterior legs together, almost touching at the apices of the 

 femora. The antennae are thus loosely held in position, while the 

 tarsi are employed to smooth forward any disarranged hairs into 

 their natural position. I have not observed any special cleaning 

 structure, such as that which obtains in certain Hymenoptera, 

 &c. During this, the insect is distinctly raised up in front by 

 means of the intermediate legs. 



One of the individuals I am observing has lost the apical two 

 segments of the left antennae, and, although this seems to have 

 no absolutely deleterious effect upon the bug, it is evidently 

 causing her a great amount of anxiety. She appears to be much 

 perplexed at the shortness of the antenna, and repeatedly strokes 

 it between the two anterior legs ; there does not, however, seem 

 to be any actual pain connected with the loss. The antennae are 

 probably auditory organs — certainly not tactile — as directly the 

 bug approaches an obstruction, the antennae are thrown back out 

 of harm's way, almost at right-angles to the longitudinal plane 

 of the body. It may be noted that the eyes are enormously 

 developed in this genus and its allies. 



The legs are cleaned in much the same manner as the an- 

 tennae. The pubescence on the head is smoothed by the tarsi of 

 the posterior legs (one at a time), the latter being very long and 

 flexibly- segmented. The attitude of H. pygmaea during this part 

 of its toilet is very funny, reminding one irresistibly of a dog 

 scratching his ear. The posterior tarsi are also brought into 

 play for the cleansing of the connexival (and abdominal) 

 pubescence. In the macropterous individuals, the flight-organs 

 are slightly lifted up, the posterior legs (one at a time) moving 

 underneath them, arranging the pubescence. 



Attention to the ventral parts of the body is a rather more 



