ACANTHOPSYCHE OPACELLA. 885 



spun, thin in texture and the mouth is closed by drawing the sides 

 together from the inside. The interior of the case is composed of 

 whitish, smooth, closely spun silk, rather thin in texture (semitrans- 

 parent if held up to the light). Adult cases from Bournemouth were 

 22mm. in length, 5mm. in thickness, cylindrical, tapering slightly 

 posteriorly, covered with flakes of black wood or bark of pine trees, also 

 some grains of sand and a few minute pieces of stone (Bacot). A spun- 

 up case from Rannoch (taken by Mr. Reid) is nearly 22mm. long, and 

 about 4 -5mm. in width, at the broadest part, slightly tapering towards 

 the free (emergence) end and with finer material there than lower down, 

 the silken tube closely covered with small particles of plant debris, 

 outside which are larger pieces of plant stems, pine-needles, pine bark, 

 &c, fastened at about an angle of 30°-40°, the outer ends point- 

 ing towards the free end of the attached case. There are fewer 

 needle-like pieces of grass, stems, &c., towards the anterior (spun 

 down) end than towards the posterior, where the flattened pieces of 

 pine bark are more abundant. Chapman notes of the cases in 

 Constant's collection that " they are distinctly smaller than those of 

 P. villosella, covered with various materials — leaves, grass, stems, &c. — • 

 whilst the colour of the silk and the terminal portions of the case are 

 very much like those of P. villosella ; the ' silken cap ' is somewhat 

 lengthened and, in some aspects, the case is not unlike that of C. 

 unicolor although the front portion is not so bold." The case is about 

 an inch in length, composed internally of soft, tough silk, and covered 

 with small pieces of dried grass, pointing backwards, morsels of bark, 

 seed-capsules, and other dried vegetable substances (Barrett). The 

 case is from 10-12 lines long, 3 lines wide, generally dark-coloured, 

 with short and thin pieces of plant stems, leaves laid lengthwise, and 

 here and there grains of sand. It resembles that of C. unicolor but 

 tbe pieces of plant do not stick out as is commonly the case in the 

 latter. The male case ends in a long, very apparent white tube 

 (Hofmann). A. Hoffmann notes the cases found on Calluna and 

 Vaccinium in the moor region of the Upper Hartz, as being " nearly 

 2cm. in length, moderately uniform throughout in width, the diameter 

 being about "450111. ; the cases irregularly clothed with longish grass- 

 culms, pine-needles, and other parts of plants placed longitudinally; 

 the tube of the $ case about - 5cm. long, parchment-like, and 

 white." Bang-Haas says that tbe case is narrow, 8 lines-10 lines long, 

 covered to beyond the middle with grains of sand, small particles of 

 leaf and fragments of grass, whilst the white silken tube projects 

 beyond for about a third part of the length of the case at its free end. 



Habits of Larva. — Mrs. Cowl writes that, in 1898, when the young 

 larvae of A. opacella hatched, they wandered about aimlessly on their 

 two front pairs of legs, the abdomen in the air and refused to touch 

 sallow or any other food, until they had first constructed themselves 

 little cases of silk, covered with silver sand and minute particles of 

 lichen which were woven into the silk. As soon as their bodies were 

 covered they ate freely the sallow offered them, and a few fed up well 

 all the summer and autumn. Two or three of them hybernated almost 

 or fpiite full-grown, attached firmly to a sallow branch by silken 

 threads (in litt., February, 1899). Bacot notes that two lame 

 emerged from a puparium (obtained at Locarno) on April 23rd, 1899, 

 and were followed on the morning of the 24th, by some two or three 



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