426 MEANS OF DEFENCE OF INSECTS. 



some shelter themselves under an umbrella formed of their own excre- 

 ment ! You will exclaim, perhaps, that there is not a parallel case in all 

 nature ; it maybe so; yet as lam bound to confess the faults of insects 

 as well as to extol their virtues, I must not conceal from you this op- 

 probrium. Beetles of three different genera are given to this Hottentot 

 habit. The first to which I shall introduce you is one that has long been 

 celebrated under the name of the beetle of the lily (Crioceris merdigera, 

 Cantaride de" Gigli Vallisn.). The larvae of this insect have a very tender 

 skin, which appears to require some covering from the impressions of the 

 external air and from the rays of the sun ; and it finds nothing so well 

 adapted to answer these purposes, and probably also to conceal itself from 

 the birds, as its own excrement, with which it covers itself in the following 

 manner. Its anus is remarkably situated, being on the back of the last 

 segment of the body, and not at or under its extremity, as obtains in most 

 insects. By means of such a position, the excrement when it issues from 

 the body, instead of being pushed away and falling, is lifted up above the 

 back in the direction of the head. When entirely clear of the passage, it 

 falls, and is retained, though slightly, by its viscosity. The grub next, by 

 a movement of its segments, conducts it from the place where it fell to the 

 vicinity of the head. It effects this by swelling the segment on which the 

 excrement is deposited, and contracting the following one, so that it ne- 

 cessarily moves that way. Although, when discharged, it has a longitu- 

 dinal direction, by the same action of the segments the animal contrives 

 to place every grain transversely. Thus, when laid quite bare, it will 

 cover itself in about two hours. There are often many layers of these 

 grains upon the back of the insect, so as to form a coat of greater diameter 

 than its body. When it becomes too heavy and stiff, it is thrown off, and 

 a new one begun. 1 The larvae of the various species of the tortoise- 

 beetles (Cassida L.) have all of them, as far as they are known, similar 

 habits, and are furnished besides with a singular apparatus, by means of 

 which they can elevate or drop their stercorarious parasol so as most ef- 

 fectually to shelter or shade them. The instrument by which they effect 

 this is an anal fork, upon which they deposit their excrement, and which 

 in some is turned up and lies flat upon their backs ; and in others forms 

 different angles, from very acute to very obtuse, with their body ; and 

 occasionally is unbent and in the same direction with it. 2 In some species 

 the excrement is not so disgusting as you may suppose, being formed into 

 fine branching filaments. This is the case with C. maculata L. 3 In the 

 cognate genus Imatidium, the larvae also are merdigerous ; and that of /. 

 Leayanum Latr., taken by Major- General Hardwicke in the East Indies, 

 also produces an assemblage of very long filaments, that resemble a dried 

 fucus or a filamentous lichen. The clothing of the Tineas, clothes-moths, 

 and others, and also of the case-worms, having enlarged upon in a former 

 letter, I need not describe here. 



Some insects, that they may not be discovered and become the prey of 

 their enemies when they are reposing, conceal themselves in flowers. The 

 male of a little bee(Heriades 4 Campanularum),a true Sybarite, dozes volup- 

 tuously in the bells of the different species of Campanula in which, in- 



1 Reaum. iii. 220. Compare Vallisnieri, Esperienz. ed Osservaz. 195. Ed. 1726. 



2 Reaum. 233. 5 Kirby in Lin. Trans, iii. 10. 

 * Apis. * *. c. 2. y- K. 



