LACHNEIS LANESTRIS. 511 



In a breeding-cage they are spun to twigs, in curled leaves, or in a corner 

 of the cage, and sometimes seven or eight are spun together so firmly 

 that they cannot be separated without injuring the cocoons (Massey). 

 Greene notices that he once found two cocoons, in October, at roots of 

 elm, no hawthorn being near at hand. Battley finds the cocoons 

 among dead hawthorn leaves, and Robson says that the larvae generally 

 spin up among the rubbish about the bottom of a hedge. Lambillion 

 observes that the cocoons are made up under moss or grass not far 

 from the feeding-places of the larva? ; whilst Ridley says that they are 

 sometimes made quite openly, and in winter may be found attached to 

 stems of hawthorn. 



Cocoon. — The larva spins a compact, oval, brown cocoon, about 

 three-quarters of an inch long, and rather more than three-eighths 

 broad. The inside of the cocoon is paler than the outside, and looks 

 smooth to the naked eye, but it is really lined with yellowish silk which 

 appears to be quite glossy under a lens. The silk forming the outer 

 part of the cocoon is hardened with a paste composed of calcium 

 oxalate, the silk comprising but a small part of the whole. The latter 

 forms a very loose and open framework which is first constructed by 

 the larva, and serves as a foundation for the oxalate of lime which the 

 larva pours upon it. This latter is secreted by the Malpighian tubules 

 of the larva, and appears to be poured from the anus. Hewett says : 

 The lid of the cocoon is plainly visible long before the moth emerges, 

 and chips off with quite a clean edge. The cocoon itself is made of two 

 distinct layers, the outer hard and with air-holes, the inner soft, of the 

 texture of very fine brown paper without any holes at all. The two 

 separate pretty easily if a cocoon be pulled to pieces. Borkhausen says 

 that the cocoon is like that of L. everia, but is not internally lined with 

 hairs as in the latter, but with threads. To facilitate the emergence 

 of the imago the cocoon is provided with a lid, and in the side it has a 

 "Luftloch." 



Double and composite cocoons. — Cocoons containing two (and more) 

 pupa? are occasionally found in this species, i.e., the cocoon has been 

 spun in common by the larvae, and utilised for pupation. Hoffmann 

 (of Thurnau) in 1802, writes {Naturforscher, xxix., p. 230) that, on 

 August 9th, 1799, he found a nest of 26 almost full-fed larvae of L. 

 lanestris on a birch in a wood on the mountains. They soon spun up, 

 not one died, but fourteen made separate cocoons, six of the others 

 spun up two by two in common cocoons, and six others three by three, 

 so that they only made nineteen cocoons between them. Opening 

 nearly all the double and triple cocoons, easily distinguishable by their 

 larger size, he found that only one larva (one of a three) had failed to pupate. 

 Not one emerged in 1800, but they were all quite healthy at the end of 

 May. Russell observed that, of a large brood he reared, some spun 

 double cocoons, whilst in other instances a general cocoon was formed 

 by three or more of the larvae. As imagines only emerged in one or 

 two instances from these cocoons several were opened. The majority 

 contained two dead larvae, others three, and the largest as many as 

 eleven, the larvae having failed to complete their pupation. The 

 formation of these cocoons certainly appears to have resulted from 

 the overcrowding of the larvae. Hervey records, in 1871, three or four 

 instances in which two larvae used the same cocoon with no partition 

 inside. Hewett records, in 1890, an unusually large cocoon, containing 



