Insects. 1449 



deeply and closely punctured, nose and mandibles black, antenna) 

 piceous ; the thorax has a central longitudinal channel, and a slight 

 parallel scratch on each side; the tegulae piceous; wings fuscous; ab- 

 domen clavate, the margins of the first and second segments slightly 

 depressed, the apex obtuse. 



The male closely resembles the female, but the labrum and clypeus 

 are white, and the apical segment terminates in a bifid mucro ; the 

 sixth segment has a central elevated carina ; beneath, the margins of 

 the segments are piceous. 



This species has by most authors been considered a parasitic in- 

 sect. Such was the opinion of St. Fargeau, but M. Spinola published 

 a memoir upon the genus, in which he states that they excavate bram- 

 ble-sticks, &c, and provision their own nests, and Mr. Thwaites has 

 carefully traced their economy ; he found them in bramble-sticks, 

 each stick containing the bee in various stages of development up to 

 the pupa. Since I received a communication from Mr. Thwaites 

 upon the subject, I have myself bred the insect. I observed the pa- 

 rent-bee enter a bramble-stick ; after securing the bee I cut off the 

 stick, and upon examining it, I found only two cells completed, 

 which subsequently produced each a female Ceratina. I have 

 observed Ceratina entering sticks excavated by Osmia leucomelana, 

 and think it probable that she sometimes makes use of a ready-made 

 burrow, coating it and adapting it to her purposes ; such occurrences 

 have been observed, as in the case of Megachile centuncularis, re- 

 corded by Mr. Newport, in which the bee filled up all the crevices, 

 &c. in a hole which she selected between the bricks of a garden-wall. 

 Osmia bicornis has been found to select the lock of a garden-gate, 

 and I have above mentioned the instance of Chelostoma selecting the 

 tubes of straws. Ceratina being destitute of pollenigerous organs, has 

 led theorists to class this genus amongst the parasites ; but observa- 

 tion proves that structural differences are insecure guides in theo- 

 rising upon the economy of insect life. 



Genus.— Eucera, Scopoli, Fabricias, Panzer, Rossi, Spinola. 

 Apis, Linnaeus, Kirby, Geoffroy. Trachusa, Jurine. 



Labial palpi 4-jointed; maxillary palpi 6-jointed : antenna? of the 

 male as long as the body : fore-wings with two complete sub-margi- 

 nal cells. 



iv 5 a 



