Insects. 2679 



from April to October, and have captured — with the exception of perhaps half-a-dozen 

 — all the wasps I have observed, I have not in all met with two dozen, all sexes in- 

 cluded : in the spring, a wasp of any species was a rarity ; and in the bank of a field 

 in the middle of Turner's Wood, Hampstead, where I have known three or four large 

 colonies established some seasons, not one existed during the present season : on se- 

 veral occasions, on warm sunny days in September, when I might have expected 

 swarms of wasps in these localities, I scarcely observed half-a-dozen individuals to- 

 gether. It will be recollected that in spring, about the 3rd or 4th of May, we had 

 two or three nights of sharp frost, and in such exposed situations as Hampstead 

 fruit trees suffered severely : how far this intense cold extended I am not aware, but 

 the scarcity of fruit this year shows its range to have been considerable : to this I at- 

 tribute in a great degree the scarcity of wasps in the locality I visited, — and such a 

 cause may of course happen when the spring flights of wasps appear in numbers or 

 otherwise, — but I am inclined to believe, from observation, that the abundance or 

 otherwise of wasps in spring depends upon the state of the weather during the winter : 

 should it prove excessively wet, and what we term a mild season, it proves destructive 

 to insect life ; the nights of the following spring, after such an excess of moisture, are 

 usually cold, and the weather altogether unsuited to the insect tribe. The present 

 year, if Mr. Bree's proposition were founded on fact (I mean as a consequent result), 

 ought to have proved one of great abundance of wasps at Hampstead, but the reverse 

 was the fact ; and although the coincidences recorded by Mr. Bree, of 1833 and 1834, 

 1848 and 1849, appear to support his proposition, I can only regard them as results 

 from the influence of causes above specified. The number of nests can by no means 

 be taken as a sure index of the abundance of wasps to be expected in the autumn ; 

 that must, I believe, entirely be the result of weather suited to their development, de- 

 pendant not only upon the state of the weather as adapted to their habits, but also as 

 producing an abundance of food : strong and weak nests are schoolboy terms, each 

 being the result — probably to a great extent — of weather and food, adapted to the 

 peculiar causes of abundance or scarcity of wasps which I have endeavoured to ac- 

 count for. — Frederick Smith; 11, Constitution Roiv, Gray's Inn Road, December, 

 1849. 



On the Economy of the Halicti. — Since the publication of my observations on a 

 mixed colony of Halictus abdominalis, Andrena and Sphecodes (Zool. 2370), I have 

 diligently followed up my investigations. In the beginning of April, of the present 

 year, I began my observations on a colony of Halictus morio at Hampstead : these 

 little bees were just beginning to make their appearance, and by the 29th were abun- 

 dant ; they continued to be so up to the end of June : all these individuals were 

 females; not a single male had yet appeared, and I searched most diligently at all 

 times of the day, once or more frequently twice a-week up to this period. Subse- 

 quently, until the beginning of August, their numbers were greatly reduced, single 

 individuals being occasionally seen : they at no time altogether disappeared. About 

 the second week in August the males began to appear, and by the end of that month 

 they abounded, which they continued to do until October ; and individuals of that 

 sex might be found when all the opposite sex had disappeared. The result of my 

 observations is in amount as follows : — The Halicti are a genus of bees differing in 

 habit from every known section of the Andrenidaa (Sphecodes probably excepted) 

 with which I am acquainted : contrary to all recorded observations on bees, the fe- 

 males appear first, and immediately set about the business of their economy, forming 



