502 



PSYCHODA PTEROMYS. 



atter is entirely destitute, being moreover of very 

 small size compared with the males. The wings of 

 the males are semi-transparent, being 1 clothed with 

 hair rather than scales, a peculiarity characteristic of 

 the Trichoptcra, with which order these insects are 

 still more nearly allied by the habits of the larvae, 

 which reside in cases formed of bits of twig's, leaves, 

 &c. woven with silk. The following observations, com- 

 municated by Mr. Ingpen to Mr. Stephens, will be 

 read with interest, involving as they do a curious 

 point in physiological entomology : 



" In June last I procured -a considerable supply of 

 both larvse and pupae of Psyche fttsca, found at Horn- 

 sey Wood, upon the hazel, sallow, &c., some only I 

 half the size of the others, from the largest of which I I 

 obtained four males and two females in the beginning | 

 of July ; the larvae in the smaller cases being still j 

 (Nov. '24) alive, from which I conceive 'that they I 

 remain at least two seasons, if not more, before they j 

 attain perfection, which opinion is strengthened by | 

 the fact, of my taking the young larvae*, on 17th 

 July, 1827, under three-fourths of a line in length, 

 including the case, which are now but four lines long, 

 and which I fed at first on the leaves of the sallow, 

 the cuticle of which they devoured, and with the downy 

 portion they formed their cases ; during the winter 

 they remained fixed to the upper part of the inverted 

 glass in which they were placed (having made the 

 sides easy of ascent by .covering them with a fine 

 silken web), and in March they began to stir, when I 

 supjilied them with the buds of whitethorn and after- 

 wards with sallow ; they gradually increased the size 

 of their cases, and added to them fine saw-dust and 

 pieces of leaves, and after a few weeks they again 

 became immoveably fixed, and from each of them the 

 chalcideous parasites mentioned in the note were 

 produced, and their extremely slow growth not only 

 indicates their anomalous longevity, but satisfactorily 

 shows why they are so obnoxious to the attacks of 

 the parasites. The females never leave their cases," 

 hence, Mr. Stephens adds, " how the union of the 

 sexes takes place it is difficult to imagine, as the female 

 does not leave her birth place, and the extraordinary 

 smallness of the latter sex is very remarkable." 



The genus, as restricted by English authors, com- 

 prises only a single species Psyche fusca (Haworth), 

 the male of which is three-quarters of an inch in ex- 

 panse, whilst the female is only one-sixth of an inch 

 long ; the wings on the male are entirely pale brown. 

 The French entomologists, however, introduce into 

 the genus the numerous small species, composing the 

 genus .Fitmea of Haworth, which differ only in the 

 rounded form of the wings and the straight pectination 

 of the antennae. 



PSYCHODA (Meigen). A genus of minute di- 

 pterous insects, belonging to the family TipiiMce and 

 subfamily Cvliciformes, having the wings broad, lance- 

 olate and deflexed at the sides when at rest, the legs 

 placed at equal distances, and the antennas composed 

 of a series of globular joints. These little flies have 

 the body, winsis, and antenna? clothed with long hairs 

 which, with the position of the wings when at rest 

 and their large size, give to them the appearance of 

 very small moths. . They are found in damp places, 

 and some of the species may often be seen on the 



* "Which larvse, although taken so young, produced a great 

 abundance of chalcideous parasites. in June last, the eggs of 

 which must either have been deposited in the young larvae upon 

 leaving the eggs or in the latter, if not introduced upon the 

 leaves upon which they were nourished," 



windows of our apartments. There are about a 

 dozen species, the type being the I 1 , pkalfnoidtt of 

 Latreille. 



' PSYLLID^E (Latreille). A family of homopter- 

 ous insects, belonging to the division Aphidicnx, La- 

 treille, having the antenna? composed of ten or eleven 

 joints, the last being terminated by two setae ; the 

 legs are formed for leaping ; tarsi two-jointed. These 

 are small active insects, found upon various vegetables 

 upon which they form gall-like excrescences, by 

 wounding the tender parts of the plants with their 

 rostrum, ibr obtaining a supply of food. The larva 1 

 have the body flat, the head large, and abdomen ob- 

 tuse behind. The perfect insects are very active, and 

 the females deposit their eggs in the midst of a ma?s 

 of a white downy secretion. The family comprises 

 three genera,P.vr///f/, having the antenna 1 filiform, com- 

 prising numerous species (the type beinir the Clicrnicn 

 bu.ii, Linn<us)and Livia, having the antennae short and 

 very thick, and Li villa, Curtis's Hrit. Knt. pi. (ij.'i 



PTEROCARPUS (Linmeus). A senna of tro- 

 pical trees, belonging to Linnaeus's class Afomtdeiphia, 

 and to the natural order LegttnitnoKt. The species 

 are treated as stove plants, and are easily increased 

 by cuttings. P. draco is one of the trees which exude, 

 when cut, a reddish sap, called dragon's blood. This 

 resin was formerly exported in great quantities from 

 Carthagena ; but, from diminished consumption of 

 the drug, its collection has ceased ; the produce of 

 Calamus draco being now used as a substitute. 



PTEROCERAS(Lamarck;STnoMBis, Linnaeus). 

 These molluscs have been separated from the Lin- 

 na:an Strombi, in consequence of their not having the 

 canal at their base shortened, or truncated, as is tin- 

 case in the Strombi; it is, on the contrary, elongated 

 in the form of a tail attenuated to its extremity, and 

 generally closed in adult examples, the right margin 

 dilated by age into an expanded digilatt-d wing, at- 

 tached to and covering the whole of the spire ; the 

 lower part .interrupted by an interval or wide gap. 

 This is not contiguous to the body of the .'hell (as in 

 the lioste/laria), but distant and similar to that of the 

 Stromhns, which is only distinguished from this genus 

 by the short canal and the want of diyitations ; we 

 are therefore disposed to agree with the classification 

 of Linnaeus, particularly as a knowledge of the animal 

 does not point out sufficient reason for separating it 

 from the Strombns, which it closely resembles in all 

 its organisation. Lamarck uses the term dictations 

 generally for that portion of the shell which, in some 

 species of this srenus, may be more properly called 

 claws, whence the trivial name of scorpion, or spider 

 shell. In young molluscs of this genus these are 

 not produced. The name given by Lamarck to this 

 genus is derived from two Greek words, meaning a 

 horn and a wing. Nearly all the species are inhabit- 

 ants of the Indian ocean, and many of them exhibit 

 the most beautiful colours on their lower or internal 

 surface. Very few species are known in a fossil state. 

 In Swainson's Exotic Conchology these molluscs are 

 more faithfully and more exquisitely figured than in 

 any other work extant. 



PTEROMYS Winged Mouse, or, more strictly 

 speaking, Winged Squirrel. A very remarkable genus 

 of rodent animals, formed, in some parts of their 

 bodies, like the pelaitrl&ta, or flying marsupial animals 

 of Australia ; but unlike them, and resembling the 

 squirrels properly so called, in the structure of their 

 teeth and in their general habits. They are furnished 

 with large clavicles for their size, which gives a 



