38 



Ritchie (A. H.). Ticks. — J/. Jamaica Agric.Soc, Kingston, xxi, no. 7, 

 July 1917, pp. 266. 



Evidence from stock owners as to the advantages of freeing cattle 

 from ticks by dipping or spraying is recorded. Losses are said to have 

 been reduced from 15 per cent, to vanishing point, while the value of 

 the animals has increased by about 40 per cent, since tick-eradication 

 work was started. 



Ingram (A.) & Macfie (J. W. S.). The Early Stages of Certain West 

 African Mosquitos. — Bull. Eniom. Research, London, viii, no. 2, 

 December 1917, pp. 135-154, 4 plates, 8 figs. 



Emphasis has been laid on the importance of larvae in specific 

 determination, since " many species of Culex are of uncertain identity 

 without the associated larvae, while some Aedes have identical adults, 

 yet dissimilar larvae. The characters of the larvae lie in the 

 modification of the chitinous appendages and the arrangement of the 

 hairs. As these are fully retained by the cast skins, it is possible to 

 preserve both the larva and the adult of the same identical specimen, 

 thus assuring absolutely correct associations." Following this plan 

 the authors have reared various West African mosquitos the larvae of 

 14 being here described, and they point out, that, so far from crab- 

 hole mosquitos being harmless and negligible, as has been stated, Culex 

 tJialassius, Ochlerotatus irritans and Anopheles costalis especially are 

 vicious biters and invade houses, while the last is a proved carrier of 

 malaria. 



The species here dealt with are : — Anopheles marshalli, Theo., 

 breeding in a Pistia-covered pool ; Stegomyia simpsoni, Theo., breeding 

 in holes in trees ; S. unilineata, Theo., found in a hole containing a 

 small quantity of water in the trunk of a flamboyant tree {Poinciana 

 regia) ; Mansonioides africanus, Theo., breeding in pools and swamps 

 in which Pistia stratiotes is growing, but hitherto not found in 

 association with any other water-plants, the larvae being most plentiful 

 during the rainy season, which reaches its height in June. The eggs are 

 laid in clusters of about 150 on the under- surf ace of the leaves of 

 P. stratiotes, which become nearly horizontal as the plant unfolds, thus 

 bringing the eggs into contact with the water with their pointed ends 

 downwards. On hatching, the egg breaks horizontally at its widest 

 point and the detached cone-shaped piece falls to the bottom ; the larva, 

 on escaping, also descends to the bottom and attaches itself to the root 

 of a Pistia plant, selecting a delicate rootlet and not the main tap-root 

 as the older larvae do. 



Ochlerotatus albocephalus, Theo., breeds in various situations such as 

 small cavities washed out by the sides of cement drains running across 

 an open and wind-swept golf course, an empty grave in the Accra 

 cemetery, broken pipes, earth drains, pools and crab-holes ; 0. tninutus, 

 Theo., in crab-holes ; 0. apicoanmdatus, Edw., and Cyathomyia fusca, 

 Theo., in water containing rotting leaves, etc. The larva of Eumelano- 

 myia inconsjncuosa, Theo. , is further described. The larvae of Cidex tha- 

 lassius, Theo., are found in widely different situations such as a brackish 

 lagoon, the water of which contained 680 parts of chlorine per 100,000 

 and was exposed to the full heat of the sun, fresh water pools, foul- 

 smelling water-holes, earth drains, an iron pot and a spring, so that a 



