74 THE entomologist's record. 



hairs serve to buoy up the larva when it drops on a thread, and allow 

 of its floating to a greater distance than it otherwise could. They are 

 not present in the larvne of any other British Liparids, and the only 

 other larva3 that I am acquainted with, in which similar hairs occur, are 

 those of Litliosia complana and L. r/rineola. The bulbs on the hairs of these 

 species are, however, not so well developed as in P. monacha and 0. dis- 

 par, and are not attained until after the 1st moult. It is also signifi- 

 cant that in their 1st skins the tubercles of L. complana and L. f/nscola 

 are single-haired, whereas, after the moult, the arrangement of hairs 

 corresponds closely with that of P. mnnacha and 0. dispar, the anterior 

 trapezoidals being single-haired, and the posterior many-haired. 

 After the first moult, both P. monacha and 0. dispar lose these bulbed 

 hairs. The anterior trapezoidals are, if anything, smaller, relatively 

 to the posterior ones, than before ; they, however, bear several weak 

 hairs instead of one. In addition to the large eversible glands, P. 

 monacha and 0. dupar have a small yellow gland on either side of the 

 medio-dorsal band, on each of the 1st to 4th abdominal segments. 

 These are very similar in appearance to the eversible glands, but are 

 much smaller and relatively taller. I have not observed any movement 

 of these glands, such as takes place in the latter. In their later 

 stages, there are practically no structural alterations of any moment, 

 and the larvae are so well known that it seems unnecessary to describe 

 them in detail. P. monacha larvfe, when young, are probably protected 

 by their resemblance to a bird's dropping, and in their later stages by 

 their lichen -like coloration. The larva of 0. dispar, though far from 

 noticeable on rough bark, has, at close quarters, a repulsive appearance, 

 and hardly suggests an appetising morsel, even to a bird. 



Leucoma salicis.— 1st stage, dark coloured, tapering slightly from 

 head to anus. I have not succeeded in tracing the anterior trapezoidals 

 in this skin ; they are probably present in some larvae, at any rate, 

 as I have found them in a few larvae in later stages, but they 

 were exceedingly minute. The posterior trapezoidals and lateral 

 tubercles are large and well developed, bearing numerous hairs ; pale 

 spots are present where the dorsal glands are afterwards developed. 

 The larva spins leaves together, and feeds between them in this stage. 

 A slight cocoon is spun, in which to undergo the moult ; in later stages 

 this is usually spun in a crevice of the bark. 2nd stage : The head is 

 relatively smaller, and the larva, after feeding, is somewhat slug- 

 shaped. A pale dorsal band is present, in the centre of which is a 

 narrow black streak, both band and line being interrupted on pro- 

 thorax, 1st, 2nd, 6th and 7th abdominal segments. In addition to 

 the usual eversible glands, L. salicis possesses a pair of small, round, 

 flask-shaped glands, placed close together near the centre of 1st and 2nd 

 abdominal segments. In later stages a drop of clear viscous-looking 

 fluid is exuded from the top of these glands. The larvffi endeavour to 

 roll in a ring if disturbed. In the 3rd skin considerable variation in 

 colour occurs, some larvae being almost entirely black, while others 

 have the white dorsal band well developed. 4th skin : The larva now 

 attain their well-known adult coloration, which Poulton considers to be 

 a good example of warning coloration. One larva of a brood I reared 

 in '96, possessed only one white dorsal spot, that on the meta-thorax 

 and 1st abdominal segment, all the remaining spots of the chain 

 being of the same tint as the ground-colour. In its last stage, this 



