250 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Life-history of Warble-Flies.*— G. IT. Carpenter, T. R. Hewitt. 

 and T. K. Reddin report some new facts in the life-history of warble- 

 flies. Like Glaser and Hadwen, they have previously demonstrated 

 that the eggs are hatched while iixed to the hairs of the skin. They 

 also described, as Glaser did, the structure of the minute spiny first-stage 

 larva previously unknown outside the egg. Of the various results which 

 they now set forth the most important is the fact, indicated both by the 

 muzzling experiments and by direct observation, that this first-stage 

 maggot bores into the host-animal directly through the skin, as was 

 generally believed to be the case until the discovery of the second-stage 

 larva? in the gullet led to the view that the mode of entrance is by way 

 of the mouth. 



The fly almost exclusively lays its eggs on the legs, not confining 

 itself to any particular area, but Hypoderma bovis at least shows a decided 

 preference for the heel or hock-joint of the hind legs. In the case of 

 H. lineal urn, the earlier of the two flies, the eggs are laid in rows ; in 

 the case of H. bovis, the eggs are laid singly and quickly. 



On the third day the minute maggots are ready to hatch, and hatching 

 occurs on the fourth day. The first-stage larvae ((>• 8 mm. in length) 

 is distinguished by the relatively immense strength of its mouth-hooks 

 and by its spiny armature. Those described from the gullet are really 

 second-stage larvae. 



Muzzling experiments proved that the first-stage larvae bore through 

 the skin of the back. The process was observed ; it lasted for six hours. 

 Minute holes are seen, and next day these are represented by small 

 eruptions visible to the naked eye. The course of the larvae beneath 

 the skin has not yet been traced. It seems probable that the sub-mucous 

 coat of the gullet is a common resting-place, for the parasites on their 

 way to their final position beneath the skin of the back. 



The destruction of warble -maggots \ is discussed by J. L. Duncan, 

 T. R. Hewitt, and D. S. Jardine. Many substances were found to be 

 useless, many killed only a small percentage. A mixture of archangel 

 tar and paraffin is deadly, but it is harmful to the cattle. Sulphur- 

 dioxide applied under pressure individually to each maggot for less than 

 a minute kills 93 p.c. of the maggots and causes no harm to the cattle. 



Brain of Cockroach and Mealworm.^ — F. Bretschneider has made a 

 thorough study of the brain of PeripJaneta orientalis and Tenebrio molitor. 

 The brain of the cockroach is very typical with proto-, deutero- and trito- 

 cerebrum. The protocerebrum consists of optic ganglion, ocellar ganglion, 

 lobus protocerebralis, pons protocerebralis, median protocerebrum. The 

 mushroom-shaped bodies or corpora pedunculata lie in front on each 

 side of the median protocerebrum. They show with great clearness "cup- 

 glomeruli " or calices, which have not been much noticed by previous 

 investigators. Their importance lies in their fibrous connexion with 

 all the important parts of the brain. There is a sexual dimorphism in 

 the compound eyes and in the ocelli, and likewise to some extent in the 



* Journ. Dept. Agric. Ireland, xv. (1914) pp. 105-21. 

 t Journ. Dept. Agric. Ireland, xv. (1914) pp. 121-32. 

 X Jen. Zeitschr. Natunv., lii (1914) pp. 269-362 (3 pis. and 19 figs.). 



