3-10 NATTRAL ARRANGEMENT OF INSECTS. 



husk is placed upon its head and legs, and a sudden jerk 

 casts it beyond the outer circle of this pitfall. It forms 

 these cavities by shuffling backwards with its pointed 

 abdomen in a spiral direction, rejecting, as it proceeds, 

 the superfluous sand, by a jerk similar to that by which 

 it throws off the cases of the insects it has devoured. 

 It is a short plump creature, with the head flat above, 

 but convex beneath ; and the mandibles are slender, 

 forcipate at their extremity, and nearly one third the 

 length of the body. It has six short slender legs ; the 

 posterior pair being distorted in position, to facilitate 

 the peculiar regressive motion by which it forms its 

 burrow. ^Vhen arrived at maturity, it forms a circular 

 tocoon of silk, by means of the spinneret at the apex of 

 its abdomen ; and, after a short period, the insect itself 

 comes forth, and is disproportionately large compared 

 with its pupa ; for, after quitting the case of the latter, 

 it rapidly expands until it has acquired its full size ; 

 when its parts harden, and it sails forth to revel upon 

 the nectar of flowers, for it has now lost its carnivorous 

 propensities, and its Ufe henceforth is a " perpetual 

 feast of nectar'd sweets." Iteaumur has observed, that 

 they will feed upon fruits, especially plums. A fur- 

 ther confirmation of the striking differences between 

 the preceding and the present families is, that the latter 

 rarely fly during the day, but chiefly towards evening ; 

 and, in repose, their wings are roofed over them like 

 those of moths ; whereas the former fly only during 

 the brightest sunshine, and the position of their wings 

 has before been shown. Closely allied to Myrmecoleon 

 is the genus Ascalaphus. Their larvae are considerably 

 alike, but they do not, like those of the former, make- 

 conical traps ; and, besides, their progression is for-: 

 wards, and not backwards. The perfect insect is ex- 

 tremely hke a butterfly ; it has antennae as long as the 

 body, which are suddenly knobbed at their extremity; 

 their Avings are more or less triangular, and variously 

 spotted or marked ; but they have a slow and heavy 

 flight. 



