67 



moves rapidly and dives to th<> ))ottoin of the water. Recovering- from 

 its frig-ht. it rises obliquely to the surface, 



•'Just as with the larvaj of Culex, the larvte of Anopheles live upon 

 organic microscopic particles which tioat upon the water, and which are 

 broug'ht into the mouth by the movements of the rotatory organs. 

 These organs are much more developed than with the larvte of Culex, 

 and while they serve, like the former, as a brush or sieve to strain their 

 food the larvaj of Anopheles, like those of Simulium, holding the head 

 stretched forward, use them to agitate the ^\•ater. The larvae of 

 Anopheles present this peculiarity, that in producing these currents, 

 which they do the greater part of the day, they lie upon the ])elly 

 with the under pail of the head turned upward. This rotation of the 

 head is executed with the greatest rapidity; and scarcely, for example, 

 have the larva? come to the surface to float, when, b}" a rotation of the 

 head upon its longitudinal axis, it is turned bottom side upward and 

 commences to agitate the surface of the water. This agitation is 

 undoubtedly for the purpose of drawing floating objects surely and 

 completely into the oriflce of the mouth. This, however, is not neces- 

 sary, for often one sees the larva with its head working in normal 

 position, mouth organs l)elow, but in general they do not remain in 

 this position for a long time, and it is only after having turned the 

 head upward that they seem to work co7i amore. 



"As a rule the lar\'a^ seek their nourishment while they are floating 

 at the surface, but at other times they descend two or tliree inches 

 under the water. They can rest several minutes in this position with 

 the head below, after which the}' come to the surface again." 



This account shows that ]Meinert knew the larvaa very well, and one 

 can only regret that he did not describe the eggs and the pupa?. 



THE MALAKIAI. EXPEDITION OF THE LIVERPOOL SCHOOL OF TROPICAL 



MEDICINE. 



This interesting and most valuable report was known to the writer 

 only by brief newspaper notes until the present bulletin had reached 

 page proof — too late to insert in pi'oper place several important obser- 

 vations made by Ross, Annett, Austen, and Fielding-Ould. To-day 

 (August 13) it has reached him in Volume II of the Thompson Yates 

 Laboratory Reports (University Press of Liverpool, 1900), and he is 

 glad of the opportunity to add the following paragraphs (juoted from 

 its pages: 



8. METHODS FOK ASCERTAININO DEFINITIVK HOSTS. 



The long researches of one of us in India, followed by those of Koch, Daniels, and 

 the Italian investigators, have given us a verj' exact knowledge of the life history of 

 the Hsemamoebidse in gnats, and have shown us how to detect them in the insects 

 with ease and certainty. It has been noted that in inhospitable species of gnats the 

 ingested parasites perish within the stomach cavity, whereas in hospitable species 

 the zygotes escape from that cavity and develop in the tissues, ultimately giving rise 

 to blasts which are found in the juices and salivary glands of the insect. * * * 



