370 BRITISH LEPIDOPTERA. 



that when full-fed the larvae of the two sexes of some species take up 

 different positions for pupation, but Zincken stated (Germar's May. 

 -En£.,i.,p.31)that those of some species live separately on different food- 

 plants, whilst &che&l(Wien. Ent. Monats. ,i.,p. 73) makes a similar obser- 

 vation concerning Ptilocephala atra (angustella). Hofmann considers 

 that this is the explanation of our sometimes finding only males and 

 at other times only females in a given locality, and adds that the male 

 larva? usually select a low open place for pupation, exposed to the sun, 

 where they are influenced by the moisture of the dew, whilst the 

 females select an exposed position, possibly for the purpose of fertilisa- 

 tion. There are, of course, many exceptions, and Hofmann further 

 observes that he has always found the $■ and ? cases of Ptilocephala 

 atra (anyustella) at Ratisbon in the same place, although elsewhere in 

 different places. 



The male pupa (described ante, pp. 109-110,275) has two strong ventro- 

 anal hooks, and, besides the anterior dorsal spines which point backwards, 

 has a row of intersegmental spines directed forwards, on the posterior 

 portions of the abdominal segments 5-8. Bacot and Chapman have 

 noticed [Ent. Piecord, xi., p. 181) those of Stand fussia zermattensis, and 

 Chapman writes that these posterior spines are very remarkable and 

 are on that portion of the intersegmental membrane that folds in, a 

 very unusual situation for spines. When the segment is fully stretched 

 they point forwards rather than backwards. As the segments close 

 and the membrane rolls under, they will point outwards and then 

 backwards, as they disappear into the incision. They act, therefore, 

 not merely as points of purchase against the silken interior of the case, 

 but as levers. They appear to be characteristic of all Macro- Psychid 

 male and female pupae. The head-parts, antennae, and appendages are 

 well-developed and the pupa before emergence moves freely up and 

 down the silken tube of the case which serves as a puparium, and when 

 emergence takes place the $ pupa is much protruded from the 

 extremity of the case. The 5 pupa is very different from that of the 

 $ , and structurally partakes, to a great extent, of the modifications 

 exhibited by the ? imago. It is usually delicate, but in some of the 

 exotic (and a few Palaearctic) species is robust and strong. The head- 

 parts, wing-cases, mouth-structures, and appendages, all show extreme 

 modification, and the anterior dorsal hooks that characterise the male 

 pupa are usually much less well-developed in that of the female. The 

 head-piece is ventral and ill-developed, the labrum small, the maxillae re- 

 duced to a triangular wedge just outside the labial palpi, which are fully 

 exposed ; the maxillary palpi may be lost, but are generally represented 

 by a short process at the outer angle of the maxillae ; the labium is divided 

 into three portions ; the antennae are represented by small conical 

 projections ; the legs small and protuberant, &c. The ? pupa-case 

 remains within the puparium and is filled with eggs by the ? imago. 

 The pupal period appears rarely to last less than a month, often 

 perhaps longer, and emergence usually takes place at a fairly constant 

 time of day for the same species (vide, ante, p. 107). Hofmann notes 

 8 a.m. -11 a.m. for Ptilocephala atra {angustella), Acanthopsyche opa- 

 cella, and Oreopsyche muscella, 5 p.m. -7 p.m. for Canephora unicolor, 

 Pachy thelia villosella and SterrhopterLv hirsutella. 



Bodine observes (Antennae of Lepidoptera, p. 31) that the males of 

 the American Psychids have antennae " quite highly developed in 



