ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 333 



Arthropoda. 

 o. Insecta. 



Nervous System of the Larvae of Diptera." — E. Brandt has 

 continued his researches on the nervous system of insects, f In the 

 larvae of the Leptidse, Bibionidae, Therevidte, Xylophagidse, and 

 Dolichopodidfe (families whose nervous system has not hitherto been 

 examined) there are thirteen ganglia, two cephalic, three thoracic, and 

 eight abdominal. In the Leptidae, the ganglia, instead of being joined 

 by the simple commissures as in all other Diptera, are united by 

 double nervous cords, as in the adult. In the next three families the 

 two first thoracic ganglia are close to one another, while the third is 

 further off. As the adult has only two thoracic ganglia, the first is 

 evidently derived from the union of the first two of the larva. In the 

 Dolichopodidae the adult has no abdominal ganglia, and the second 

 thoracic ganglion is therefore evidently derived from the fusion of the 

 third of the larva with all the abdominal ganglia. 



Several genera and species of families which have already been 

 partially examined are also described, and the author finds that in 

 the Tabanidae the larvas have seven ganglia, and not two only, as 

 described by J. Kiinckel d'Herculais. 



Occident Ants.f — Dr. H. C. M'Cook publishes in a collected form 

 his observations on the Honey Ants of the Garden of tlie Gods, 

 which we have already dealt with in this Journal, § and the Occident 

 Ants of the American plains. 



The Occident ants build mounds of from less than half a foot to 

 more than a foot in height, round which they make a circular 

 " clearing " of grass and other vegetation, presumably by cutting it 

 away after the manner of the agricultural ants of Texas, previously 

 described by Dr. M'Cook. The mound is always covered with 

 pebbles which have been removed in the process of excavating the 

 underground chambers and galleries. Some of the pebbles so trans- 

 ported are ten times the weight of the ant, so that the labour per- 

 formed would be paralleled by that of a man if he could carry half a 

 ton up a staircase one-third of a mile high. 



The ants do not begin their labour till eight or nine o'clock in the 

 morning ; so that, as Dr. M'Cook seems not unwilling to observe, 

 " it might not be unmeet that those persons whose love of sleep 

 during late morning hours has been disturbed by the familiar Scripture 

 proverb, ' Go to the ant, thou sluggard ; consider her ways, and be 

 wise ! ' should return upon their mentors with the above-recorded 

 facts, and cite this ant, who is indeed no sluggard, as being neverthe- 

 less fond of a morning nap." The day's work, or at any rate the day 

 of outdoor work, begins by opening the gates which had been closed 



* Comptes Rendus, xciv. (1882) pp. 982-5. 



t See this Journal, i. (1881) pp. 234-5. 



% M'Cook, H. C, 'The Honey Ants of the Garden of the Gods, and the 

 Occident Ants of the American Plains.' 8vo, Philadelphia, 1882. Gf. Mr. G. 

 J. Romanes in ' Nature,' xxv. (1882) pp. 40.i-7. 



J^ See this Journal, iii. (1880) pp. 242 and 775. 



