PACHYGASTRIA. 5 



gonal reticulation with minute black points at the angles. Observers are 

 divided as to whether the eggs (of P. trifolii) be laid loosely or attached 

 to a stem of a plant (vide, posted), but in Lasioeampa (quercus) the 

 eggs appear always to be scattered whilst the female is on the wing. 

 The newly-hatched larva of Pachygastria is stated (vide, anted, vol. ii., 

 p. 461) to be quite a moult behind Lasioeampa when it hatches from the 

 egg, judged by the character of the warts, so that the latter genus 

 appears to have had at least a moult thrust back upon that period of 

 development that takes place in the egg. Writing of the generic 

 claims of Pachygastria, Bacot observes: "The first larval stages of 

 Lymantria monacha and Porthetria dispar are structurally identical and 

 only differ slightly in size and colour, and yet, taking into account 

 all the allied European and exotic species, they certainly represent 

 two well-marked groups, each of which is distinctly of generic value, 

 and many- parallel cases might be quoted. If this be granted, and 

 the very close similarity between the larvae of Odonestis pruni and 

 Eutricha quercifolia in their hybernating instars be no bar to their 

 being placed in separate genera (and the action of all the authorities 

 supports this), we may conclude that differences in the first larval instar 

 are, in the Lachneid group, of great importance, and of generic value. 

 I consider, therefore, that querciis and trifolii should be placed in 

 separate genera, the larvae in their first stages being quite distinct " 

 (in iitt.J. The adult larva of Pachygastria (trifolii) also shows several 

 structural peculiarities, but its mode of life is so different from that of 

 Lasioeampa (quercus) that one expects some variation in response to 

 environment. Both genera have similar cocoons, and the pupae are of 

 the same squat type, but Aurivillius, as we have already pointed out 

 {anted, p. 2), finds characters of the imagines which further serve to 

 separate Pachygastria from Lasioeampa. 



The Pachygastria species are limited largely to that portion of the 

 Palaearctic area that runs from France and Spain eastwards to Central 

 Asia in about the latitude of the former countries, and are localised as 

 follows : Trifolii (southern and central Europe, southern Sweden, 

 Livonia, Asia Minor, Transcaspia, Palestine, Syria, and Mauretania), 

 josua (Palestine), eversmanni (the Russian steppe district, Armenia, 

 Pontus, Taurus, Syria, Issyk Kul district, and Fergana), nana (north- 

 east Persia and Central Asia), concolor (north-east Persia). P. trifolii 

 has the widest range, and extends somewhat to the north and south 

 of the general area indicated. 



In order that one may have the necessary means of comparison, 

 we append the original descriptions of the non-British species : 



1. Josua, Staud., '' Ins," viii., p. 296, pi. v., fig-. 8 (1896).— From pupaewhose 

 larvae Heir J. Paulus found last year in the Jordan valley, we bred here in the 

 autumn some 20 specimens of this new species. Herr Paulus writes me that this form 

 must, in his opinion, especially according to the larva, be distinct from all other species 

 found by him in Palestine. As the B. josua has a large spur on its short front tibiae, 

 like B. trifolii and its varieties, Prof. Aurivillius considers it must be a variety thereof. 

 But I hold bathseba from Palestine, which has like front tibiae, and is much more like 

 trifolii, to be its local form there. Also the specimens from Palestine, which I have 

 placed as terreni (?), may belong as aberrant specimens to bathseba (therefore to 

 trifolii). But that josua cannot be a local form of the Jordan valley is proved by two 

 cf specimens of it captured near Jerusalem, which I years ago placed as a separate 

 form, but would not describe from these two specimens alone. In size B. josua varies 

 from 45 to 63 mm., the c? s mostly 45 — 49mm., the ? s 50— 55 mm. The principal 

 difference of B. foiua from all other allied species is that its brown forewings are 



