4 BRITISH LEPIDOPTERA. 



Tutt, " Proc. Sth.Lpnd.E11t.S0c.," 1898, pp. 1 etseq. (1898); Staud., "Cat.," 3rded., 

 p. 121 (1901). Botnbix, Latr., ''Hist. Nat.," xiv., p. 178 (1805). Gastropacha, Ochs., 

 "Die Schmett.," iii., p. 262 (1810) ; Evers., "Faun. Volg.-Ural.," p. 153 (1844); 

 H.-Sch., " Sys. Bearb.," ii., p. 107 (1847) ; Heyden., " Lep. Eur. Cat. Aleth.," ed. 3, 

 p. 26 (1851); Speyer, " Geog. Verb.," i., p. 412 (1858) ; ii., p 288 (1862) ; Hein., 

 " Schmett. Deutsch.," p. 206 ((859) ; Auriv., " Nord. Ljar.," p. 63 (1889). Bombyx 

 f-Lasiocampaj, Led., '■' Verh. z.-b. Wien," ii. Abb., p. 75 (1853). Ireocatnpa, Rbr., 

 "Cat. Lep. And.," pi. v., tigs. 1—2 (1858). 



The genus is diagnosed ( Verz., p. 186) by Hiibner as follows : 



Die Schwingen mit einem weissen Punkt und auch die Senken mit einem breiten 

 hellen Streif bezeichnet. — Pachy gastrin trifolii, Schiff., "Verz.," Bom. K., 4; Hiibn., 

 "Bom.," 171. P. spartii, Hiibn., "Bom.," 173, 224. P. quercus, Linn., ' ; Syst. 

 Phal.," 222; Hiibn., "Bom.," 172, 225. P. medicaginis, Ochs., "Schm.," 42, 11 ; 

 Hiibn., " Bom.," 264. 



Hiibner's genus, as here diagnosed, is heterotypical, and we have 

 already pointed out (anted, vol. ii., p. 450) that trifolii, owing to the 

 elimination of quercus as the type of Lasiocampa, becomes the residuary 

 type of Pachygastria. At the time of the publication of Hiibner's 

 Verzeichniss, Latreille and Germar's restrictions of Lasiocampa (vide, toe. 

 cit., pp. 449 — 450) had left only three possible types of this genus, viz., 

 querciis, neustria, and castrensis. In this work, Hiibner created the 

 practically monotypical genus Malacosoma for castrensis, neustria, &c. 

 (the divergent loti, which he included, not agreeing with the generic 

 diagnosis), while, from this removal of castrensis and neustria, they 

 ceased to be possible types of Lasiocampa, and left qnerciis the resid- 

 uary type of the genus. But this determination at once removed 

 quercus as a possible type of Pachygastria, and left trifolii the residuary 

 type of the latter genus. 



The European species belonging to this genus are trifolii, Esp., 

 josua, Staud., eversmanni, Evers., nana, Staud., and concolor, Christ. The 

 first of these is the only species obtained in Britain, where it is extremely 

 local, but often abundant in its restricted haunts. It is especially 

 interesting from the tendency it exhibits to form local races, and at the 

 same time the minor variations in individual specimens are so numer- 

 ous as to make it almost polymorphic, and between the pure yellow- 

 coloured extremes of ab. flava, n. ab., and the purely dark red-brown 

 extremes of ab. rufa, n. ab., there is exhibited a great range of colour- 

 variation. It may be further noted that whilst the unicolorous forms are 

 also extreme from the point of view of having no markings whatever, 

 and remind one of the unicolorous females of Lachneis and Malacosoma, 

 others have exceedingly well-developed transverse lines, in all the 

 typical forms of each colour aberration. Aurivillius treats (Iris, vii., 

 p. 151) grandis, which Rogenhofer described as a variety of P. trifolii, 

 as a distinct species belonging to the genus Lasiocampa. Christoph's 

 note, already referred to, does not conclusively prove that P. evers- 

 manni may not be really a local form of P. trifolii. It is somewhat like 

 eastern European examples of P. trifolii var. terreni, in build, colour and 

 general appearance, the females, however, scarcely larger than the 

 males. One female example from Sarepta (in the Brit. Museum coll.) 

 is suffused, inclining to buff, and reminds one a little of the peculiar 

 tint of true P. trifolii var. ratamac. 



The eggs of the species of this genus are broadly oval (often but 

 little removed from oblong in outline). The surface is shiny, and 

 apparently smooth, but, under a lens, is seen to have a very line poly- 



