AT THE MICROSCOPE. 255 



Tronibidium holosericeum (PI. XIX., Fig. 7). — I am glad to 

 be able to add a fragment on the life-history of T7'ombidiiiin holo- 

 sericeum. Walking one sunny morning at the end of March, along 

 a grassy lane, my eye lighted on a dead specimen of Carabiis 

 gramilatjts, crushed by the rude hoof of some ignorant clown. 

 On lifting it up, a remarkably fine specimen of this acarus was 

 found, absorbed with feasting on the juices of the dead Goliath. 

 A few yards further on was another crushed beetle of the same 

 kind, with a second and equally fine specimen of the same 

 acarus. These were eagerly secured, and the attempt made to 

 keep them alive, but without success, for my health and engage- 

 ments do not permit of the constant attention requisite for success 

 in such studies. Nor have I had better luck since with other 

 attempts of a similar kind. The above observation, however, 

 favours the idea that they do not (in the mature state, at least) feed 

 upon livhig prey. What are their eggs like ? What their young ? 

 Are they parasitic in their early stages, like Lcptiis ? These are 

 some of the many questions to be (and which may be) solved by 

 working naturaHsts like ourselves. Another point to note is the 

 presence of a pair of stalked compound (!) eyes of two single ocelli 

 each a These were noticed by Hermann, and furnish a good 

 example of rudimentary limbs for purposes of vision. 



Sting of Wasp (PI. XX.) is so fully explained in the description 

 of the figures, that little need here be added. It would increase 

 the interest and value of this slide to supplement it by prepara- 

 tions of other stings — as of hornet, named bees, etc. — as intro- 

 ductory to a comprehensive view of ovipositors, of which these 

 are merely a modification. One of our English observers has 

 lately laid claim to the merit (? T. W.) of propounding that the 

 sting of Hymenoptera is only a transformed leg ! ! ! The merit 

 (? ? T. W.) of being the first to enunciate this view is disputed by 

 a talented American observer. Now, if it be as stated, there 

 must either be a serious error of interpretation, or there is nothing 

 more in it than is already well recognised. Limbs are lateral 

 appendages to body-segments ; and so the la^icets may be well 

 spoken of as " modified limbs," but the sheath is a modified body- 

 segme/it, or part of such, and cannot therefore be a " limb," or 

 lateral appendage. This bare allusion to the subject must sufiice 

 for the present ; other opportunities will probably present them- 

 selves for a fuller consideration of it. 



Saws of Saw-Fly (PI. XIX., Figs. 12, 13). — This is another of 

 our friend, E. Tutte's masterly dissections of these parts. It is 

 really important that such good material should be correctly iden- 

 tified, and so render the work capable of reception into the 



