Insects. 2371 



pendicular burrow, having short passages leading to them from the common one ; 

 each contained a ball of pollen and honey about the size of a pea, on some of which a 

 small larva was feeding. I endeavoured to trace the burrows into which T had ob- 

 served Sphecodes enter ; but I did not succeed in satisfactorily ascertaining whether 

 some small cells, which in one instance I met with, were those to which the burrow 

 led, as I had previously lost the track of it : it is possible that these cells were those 

 of H. morio, — and as the food which they contained exactly resembled that found in 

 the cells of H. abdominalis, I am inclined to believe that to have been the case. 

 The food stored up by those bees which are not furnished with pollenigerous organs 

 consists of semi-fluid honey, as that of Ceratina and Hylaeus. After the most careful 

 observation of the colony, I am still inclined to believe that Sphecodes is not a 

 parasite. 



The Baron Walckenaer, in his history of H. terebrator, which is synonymous 

 with our insect, says, that it is principally during the night that these bees construct 

 their burrows ; but although I visited the colony on such nights as he describes as 

 being favourable for their operations, I never saw any bee thus employed : the nights 

 in this country are probably never sufficiently warm to favour the interesting opera- 

 tions described by Walckenaer. These bees may be seen labouring most assiduously 

 early in the morning, and also on dull warm days, but not in the great heat of mid- 

 day. Walckenaer says, that during the day either the male or female remains on 

 guard at the entrance of the burrow, retreating to the bottom on the return of either 

 from their excursions : I spared no pains in watching for an opportunity of witnessing 

 so curious and interesting an instance of insect economy, but I must admit that in 

 this account I think the Baron has fallen into an error : the female (and sometimes 

 the male) will retreat to the burrow on the sun being obscured by a cloud, or after 

 having returned from one of her excursions, and, having deposited the fruits of her 

 industry, she will on such occasions station herself for some time with her head at the 

 mouth of her burrow, as if to rest herself after her labour. The precaution described 

 by Walckenaer, he attributes to the instinct of the bee to prevent the intrusion of ene- 

 mies ; but amongst the innumerable occasions on which I have observed parasites 

 entering the nests of other bees, not a single instance ever occurred in which the 

 slightest opposition was shown ; in fact, there does not appear to be the slightest ani- 

 mosity existing between them ; on the contrary, a bee, on arriving with her load of 

 provisions, should a parasitic bee be found in the burrow, will patiently retreat, and fly 

 off to a short distance until the parasite reissues from her nest. 



At the time when I first observed the colony (about the 15th of April) and met 

 with Sphecodes subquadratus, I was anxious to secure a supply of specimens, having 

 previously only taken four or five during several years' assiduous collecting : in this I 

 succeeded, but by the end of May or the beginning of June not a bee of any of the 

 species was to be met with, and all traces of their burrows became obliterated. About 

 the middle of July I again visited the spot : a few of the burrows were again turned 

 up, the little hillocks of sand surrounding the entrances as before : I found a few 

 males of Halictus and also of Sphecodes, including the males of the Halictus morio : 

 at this time I did not observe a female of any but the latter species, but a week later 

 I found all of them in plenty, — Andrena nigro-senea having disappeared altogether 

 until next spring. 



I have now arrived at a point in the economy of Halicti which I do not know to 



