4 THE ENTOMOLOGIST. 



has occurred, the caterpillar of P. mellita is about five lines 

 long, and, like all other leaf-mining Tenthredo larva?, this 

 species lies inside its mine on its back. The frass is ejected 

 in little pellets, which are scattered about the mined part of 

 the leaf: this mostly takes place all through its larval life, 

 but instances occur now and then, when the larva is about 

 half-grown, that the pellets of frass are observed to be con- 

 nected together, reminding one, at first sight, of a string of 

 lilliputian sausages : from time to time the movements of the 

 feeding larva cause the string of pellets to assume a waved 

 and at other times an arched form ; at certain periods short 

 lengths of the cord of pellets break away from the main cord 

 by their own veight, and for a while are permitted to remain 

 in various parts of the mine, but after a time the larva, 

 as though animated with a desire to keep its mined abode 

 clean and tidy, is seen to go in search of the broken-off 

 portions of frass, and by a few dexterous movements of 

 its posterior segments to collect and arrange them into a 

 circular-shaped heap ; and from the circumstance of most of 

 the pellets of frass being linked together, they, by the 

 peculiar movements of its body, finally become arranged, and 

 assume almost as much regularity as a coil of chain : the 

 small ligatures that connect the pellets of frass together 

 1 believe to be composed of short thin threads of the same 

 substance, as it seems scarcely feasible to suppose that they 

 can by any possibility consist of silk. It should, however, 

 be observed that this remarkable arrangement of the frass is 

 not peculiar to this Tenthredo larva, for the same interesting 

 fact is at times noticeable in the economy of those savvfly 

 larva) which feed on the elm and wych-elm (Fenusa Ulmi, 

 Neivm..), the frass of the alder-mining Tenthredo (Phyllo- 

 toma microcephala. King) likewise at times assuming the 

 same appearance, and the frass of the little tenthredinidous 

 larva that blotches the leaves of the maple and sycamore (P. 

 Aceris) at times looking for all the world like a number of 

 minute black beads strung together on a thread. When 

 about three-parts grown the larva of P. mellita, if disturbed, 

 is much agitated, and lashes its body about furiously, travel- 

 ling all over its mined abode. It moults four times, and 

 some individuals, after the third moult, have, in addition to 

 their other embellishments, two black dots on the back of 



