INTRODUCTION. 3 



The habits of the Aculesites are most diverse. All are 

 believed to be vegetable feeders in the imago state, but iu 

 the larval state some feed on animal and some on vegetable 

 substances. Some nest in the ground, some in bramble 

 stems, some in gate posts ; key holes and locks prove 

 attractive to some ; old disused snail shells to others ; holes 

 in walls are utilized by certain species, and so plastered up 

 as to leave no suspicion of a hidden nest ; whilst others 

 make mud nests, and suspend them from a twig, or attach 

 them to a stem of grass. The Carder bees belonging to the 

 genus Bomhus make a covering to their nests, which are 

 placed on the ground, of moss, grass, etc., but some have 

 been kcown to utilize a forsaken bird's nest. The habits 

 of the various genera and species will be treated of under 

 their respective heads. The metamorphoses of the Aculeata 

 are complete ; the pupa3, which are either naked or 

 enclosed in a cocoon, are almost exactly of the form of the 

 perfect insect, except that the wings are enclosed in short 

 pad-like cases. The larvte are pale, fleshy, and grub-like. 

 A remarkable peculiarity exists in the transformations of 

 these creatures. The first and part of the second segment 

 of the larva unite to form the head of the imago, the fifth 

 segment of the larva, which in other insects forms the first 

 abdominal segment in the imago, is transferred during the 

 insect's passage through its pupal conditions to the thorax, 

 so that what looks like the metathorax in the imago is really 

 formed partly of the first abdominal segment, aud the 

 constriction which follows it is really between the first and 

 second segments of the abdomen, instead of between the 

 abdomen and thorax. This transferred segment has been 

 called the " propodeum," by Newman, the median seg- 

 ment by some authors ; but, for convenience sake, I shall 

 treat it here as part of the metathorax, and call the first 

 segment of the abdomen that which follows the second 

 regional constriction. 



In position the Hymenoptera should probably be placed 



