INSECTA. 



931 



and perhaps also with those of Anthophora, in 

 which, although the flight of the males is as 

 rapid as that of the females, we suspect that it 

 is not so long continued. But in Anthidium 

 manicatum the number of hooks is in corres- 

 pondence with the apparently greater power of 

 wing in the male, which pursues his partner 

 unceasingly, and darts down upon her with 

 great rapidity at the season of connubiality. 

 A similar remark is applicable to the male of 

 the hive-bee, which at the period of swarming 

 is exceedingly active, and constantly on the 

 wing in the open air, in search of the queen or 

 solitary female, who leaves the hive but for a 

 few hours on the first or second day after 

 swarming. Now we have seen that the number 

 of hooks in these males is greater than in the 

 females, and that their powers of flight are 

 also greater, and that in the Bombi the reverse 

 is the case with regard to both these circum- 

 stances. Consequently it is but fair to infer 

 that the number and strength of the hooks are 

 in direct relation to the powers of the insect. 



We have before remarked that the different 

 forms and appendages of the body are invariably 

 the result, not of the introduction of new 

 elements into the composition of parts, but 

 of the greater or less extent to which those 

 primary parts are developed. There is a beau- 

 tiful illustration of this principle in the develop- 

 ment of the hdftiuli, which are only spinous 

 processes often observed on the wings of other 

 insects. In proof of this we need but examine 

 the wing of the common working-bee, in which 

 there are several of these spines arranged in 

 a line with the hamuli, and inserted in a similar 

 manner into the nervure of the wing upon which 

 the hooks are situated. In some instances the 

 transition of form from that of spines to hooks 

 is distinctly marked. Those which are most 

 distant from the proper hooks retain the perfect 

 form of spines, while those which are nearest 

 are bent in the same direction, but to a less 

 extent than the pre per hook, but sufficiently so 

 to mark very distinctly their proper analogy. 



In Hemiptera, instead of being connected by 

 hooks as in Hymenoptera, the whole margin 

 of a portion of the anterior wing is hooked over 

 a corresponding recurved part of the posterior, 

 as formerly noticed by Chabrier* in the Penta- 

 tomidtf. In the Homoptera the wings are con- 

 nected in the same manner as in Hemiptera, as 

 noticed by Mr. Ashton-f in Membracis cornuta. 

 This is also the case in other Homoptera. Thus 

 in Tettigonia bifasciata there is a triangular 

 membranous process extending from the anterior 

 margin of the inferior wing, and which on its 

 distal border is furnished with four very dis- 

 tinct but exceedingly minute hooks, resembling 

 those of Hymenoptera. This process of the 

 posterior wing is curved a little upwards and 

 received into a fold of the posterior margin of 

 the anterior wing. There is a similar structure 

 in the wing of Cercopis sanguinolenta, with 

 this difference, that the hooks are very indis- 



* Sur le Vol des Insectes. 



t Proceedings of the Entomological Society of 

 London in Transactions, vol. ii. p. 20. 



tinct, while the triangular process of the wing 

 is more pointed and hooked upwards. In 

 Tettigonia spumaria the structure is exactly 

 the same. In lassus viridis the triangular 

 process is shorter, but more extended along 

 the costal margin of the wing, and is furnished 

 with a great many very minute imperfectly de- 

 veloped hooks, which attach themselves to the 

 folded linear margin of the anterior wing. 



The legs, the proper organs of locomotion, 

 are constantly six in number in every order of 

 insects, but are subject to much variety of form. 

 Each leg is composed of five distinct parts. 

 First, (Jig. 332 and 398,) the coxa (a) or basial 



Legs of insects, from Bttrmeister, Curtis, and Hope. 



joint, which is inserted into the acetabulum, 

 and connects the limb with the thorax. Of 

 this part the trochantin is believed to be an 

 appendage. Secondly, the trochanter, a 

 minute joint attached to the extremity of the 

 coxa. It is not lettered in our figure of the leg 

 (Jig. 332, 3, 4), but is placed between the 

 coxa and the third portion of the limb, the 

 femur (6), with which it is freely articulated. 

 The femur is the proper thigh of the insect, and 

 in general is of considerable size. It is con- 

 nected by ginglymoid articulation to the fourth 

 portion of the limb, the tibia (c), which is 

 usually a long slender joint, at the extremity of 

 which is articulated the fifth and last portion, 

 the tarsus (<f). This part is always composed of 

 several distinct joints, varying in number in 

 different insects from two to six. The more 

 common number is five. These are the pri- 



3 P 2 



