170 



The Natuealist. 



a severe smarting sensation of pain, and smelling palpably of nitric 

 acid. I could have testified to its identity. It produces likewise a 

 similar yellowish effect. Dr. Palmer, of Fort Beaufort, assures me 

 that venomous reptiles, and various other vertebrates, discharge formic 

 acid. A friend sent to me a singular fish, one of the PlectorjnatJd—2i 

 species of Tetraodon* (Plate vi.), first cousin to Diodon, referred to by 

 Darwin in his " Beagle Experiences." The specimen was quite fresh, 

 and recently captured. I had it preserved, and the taxidermist told 

 me that his venturesome cat, intruding too imprudently within meic- 

 seum precincts, bit off forbidden flesh, and biting — died — a poisoned 

 thief. Formic acid again, no doubt ! The spines of Tetraodou, 

 I believe, affected my flesh, and' this fact suggested the following 

 query to my mind, viz. : — When Tetraodon is inflated, floating help- 

 lessly on or near the surface of the sea, does it discharge poisonous 

 matter at will for self -protection ? "It fills with air a thin and 

 extensive membranous sac, which adheres to the peritoneum the whole 

 length of abdomen. When thus inflated it rolls over and floats belly 

 upwards, without any power of directing its course." When the tiger 

 claw (1) jaws of this peculiar fish are brought to market, they may 

 realise a fancy price. 



You will remark Hymenoptera and Diptera in my list are classed 

 co-equally, but I omit Formicid^ from the former. The ants constitute 

 a world unto themselves. An interesting species of Odynerus has often 

 arrested my attention. It makes a nest in the stalk of some OrnitJio- 

 galum, and continues a recess for concealing or burying carcases of 

 larval-slaughtered Diptera. Another species I took, some time ago, 

 alive in a mud cocoon of some lepidopterous insects. There was no 

 hole of egress. One remarkable wasp — a rarity — deserves special 

 treatment. Its body is covered with a soft greyish flavescent pile, 

 sparingly distributed, black antenna thickly pectinated, longer than 

 thorax, thorax and scutellum deeply rufous, metathorax distinct, 

 shapely and tuberous. Abdomen : base of seg. 1 having narrow 

 greyish fulvous band, discontinued beneath. Middle of seg. 3 wdth 

 corresponding band, broader, extending around abdomen, narrowing 

 on under side. Legs pilose, apical tibial spines conspicuous and 

 fulvous. Wings : smoky black, of varying depth, glossy and semi- 

 transparent, with dark-blue tinge, obscuring towards disc, and forming 

 a distinct dirt}^ band. Fore wings having a decided grey streak, 

 bisecting radial areola to nerve and continued almost at right angles to 



* Trimen. 



