82 THE entomologist's record, 



I have never seen the male in the act of flyinpj spontaneously, but 

 we caused several to take the air by throwing them up. These flew 

 rai)idly and turned very sharplj^ — darting forward and doul;)ling back 

 suddenly, so that they would be difficult to catcli on the wing. 



In considering the possible causes of this aljnormal al)undance of 

 the species in 1893, I will first deal with an important factor in the 

 situation — the weather, beginning at the point when we commenced our 

 search for the species, February, 1890. In 1890 one imago was found. 

 Spring probably moderately favourable for larvEe. In 1890-91, winter 

 unusually rigorous ; 1891, February very favourable for appearance of 

 imago, none however found. March, April, and May cold, spring- 

 very backward, and perhaps unfavourable to larvae ; 1891-92, winter 

 again severe ; 1892, spring rather favourable to larvae ; October, a wet 

 month ; November, fairly dry, temperature, average ; December dry, 

 the first week cold, with low night temperature ; then a fortnight of 

 warm weather ; the last week exceedingly coLl, 17 to 18 degrees of frost ; 

 1893, January, rather dry but cold, es[)ecially the early part of the 

 month ; Feljruary, a wet month, with temperature above the average ; 

 March, April, and May, extremely dry; larvae (I am told) plentiful. 

 The probable effect of the cold winters of 1890-91 and 1891-92, would 

 be to keejD down the depredations of the moles, mice, beetles, earwigs, 

 &c., by extending the length of time which they spend in a state of 

 tor})idity, and possibly to reduce the numbers of these enemies to pupte. 

 No imagines were found by us in either 1891 or 1892, though February 

 of the first-named year appeared to be eminently suited for emergence, 

 but the cold dreary spring months of 1891 may have checked any 

 increase by retarding or stopping the due development of the larva\ I 

 {jm sorry, however, that I am unable to speak as to the frequent occur- 

 rence or otherwise, of the larvae in those years, for this would give a 

 truer idea of the relative abundance ; searching for the imago being 

 often obstructed by the available days happening to be cold or Avet. J 

 do not know whether the heavy rainfall of October, 1892, may have 

 favoured the pupo3. Are they liable to dry up ? As they usually, I 

 believe, bury themselves to a depth of several inches, moisture, dryness 

 or cold would not be so likely to affect them, as would be the case with 

 pujDaB lying nearer the surface. Many, however, do not inter themselves 

 so deeply, as we have found pup^e just under the roots of the grass. 

 Any advantage, too, gained by a very wet and mild season, would 

 probably be more than counterbalanced by the extra activity of the mole, 

 and other lovers of fat pupfe. 



Some other ideas suggest themselves. Immigration can scarcely be 

 an imjiortant factor in a species Avith a wingless J . It has, indeed, 

 been su})})osed, that a reinforcement of (J s might increase the fertility 

 of a species, but it seems unlikely that hispidaria should have benefitted 

 in this way, although, from its robust appearance, a long flight would 

 appear quite possible. The sudden augmentation of numbers, it will be 

 noticed, took place in a well-known locality, where the insect is found 

 in greater or less numbers, (generally the latter) every year. An 

 alteration in the fertility or irregular fertility of a species in different 

 seasons, has been suggested, but I do not know whether there are any 

 facts in support of this theory recorded in relation to the macro-lepi- 

 doptera. It might be that an unfavourable change in the weather 

 might retard oviposition by the ? , or even destroy her, and this may 



