225 



rows than when they are thrown in promiscuously. The Mantidw^ 

 which deposit their eggs in cocoons that are no longer carried, may be 

 supposed to represent an intermediate stage as far as the habits of ovi- 

 position are concerned between the Blattidw and those numerous forms 

 which either deposit their eggs in exposed situations \\k.Q Microeentrum^ 

 or bury them in the earth or the tissues of plants like the Acridiidcc 

 and GryUidcc. 



The eggs of XipMdium ensiferum begin to develop immediately af- 

 ter their deposition. During the warm days that intervene before the 

 cold of autumn sets in the embryo is formed on the middleof the flat side 

 of the yolk. The head of the embryo points downward towards the 

 insertion of the leaves between which it is placed; consequently the 

 pointed and upward directed pole is the caudal end. Tbe young em- 

 bryo remains dormant during the winter but continues its development 

 during the warm days of spring. The tir st larvse were seen to emerge 

 from the galls on the 17th of May. 



I will not here enter into the details of development, many of which 

 I have not yet observed to my own satisfaction. Suffice it to say that 

 the Locustid's ontogeny is strikingly like that of the Gryllid, (Ecanthus 

 niveas as described by Dr. Howard Ayers. The embryo, as noted above, 

 is developed on the flat ventral face of the e,gg with its head directed 

 downward. During its growth it gradually moves down the yolk till 

 its head reaches the pole, then it turns and passes up the convex (for- 

 merly dorsal) surface of the yolk till its head reaches the pointed (for- 

 merly caudal) pole; the body of the embryo meanwhile increases in 

 size and envelops the entire yolk by a very interesting process, the 

 details of which I have not, as yet, been able clearly to elucidate. Con- 

 sidering the position in which the e.gg is deposited, i. e., with its 

 cephalic pole directed downwards, a revolution like the one described 

 is necessary to bring the embryo's head to the opposite pole, so that 

 in hatching the larva may have no difficulty in crawling out between 

 the scales of the gall. 



THE SIX-SPOTTED MITE OF THE ORANGE. 



(Tetranychus 6 maculatus, u. sp.) 

 By C. v. Riley. 



This mite has done much damage to the orange in Florida since 1886, 

 and we have prepared a preliminary article for the Annual Report of 

 this Department for 1889. As it is deemed wise to exclude purely de- 

 scriptive matter from the Annual, we give here the diagnosis of the 

 species under the the name of Tetranychiis G maculatus on account of 

 the quite constant markings of its back. In color it is very similar to 

 T. rosearum Boisd., T. tiliarum Mull, and T. vitis Boisd. 



