174 



The Ottawa Naturalist 



[Vol. XXXII. 



spider resembled somewhat an enormous wasp; but 

 far from being dangerous, she had become com- 

 pletely weak and impotent. Before egg-laying these 

 females never assume the terrifying position, and it 

 is only after egg-laying, when the organism has be- 

 comed weakened by the immense drain on its mater- 

 ials, that this bizarre position becomes manifest. 



In certain cases, we have been able to provoke 

 the apparition of the terrifying position by causing 

 animals to become fatigued. 



A mantis. Mantis laticollis, when it is frightened 

 is in the habit of spreading its wings and its anterior 

 extremities, resting on its four posterior legs. It 

 swells its abdomen which at this moment produces 

 two hernias formed by two little sacs placed between 

 the two anti-penultimate abdominal rings. These 

 sacs are of a very striking color. The anterior pairs 

 are dark blue, and the posterior are red. It is not 

 always easy to force the animal to take on this 

 bizarre position. We have succeeded by shaking the 

 animal, by dragging it by one leg, and by brusquely 

 approaching it with the hand when it was on a limb. 

 This position only lasts about thirty seconds and 

 appears to necessitate a great effort. We have 

 fatigued the animal by forcing it to run inside a cage 

 until it was so weak that it could not stand up. It 



was then that it assumed the terrifying position, it 

 swelled out its abdomen, and died without changing 

 position. 



Similar effects have been observed with flying 

 lizards Draco volans and Draco fimbriaius. These 

 animals, when pressed, tried to run away; when they 

 were forced to jump they spread out their parachute 

 membranes and vol-planed for a long distance. But 

 finally when over fatigued and when they could no 

 longer run they assumed the terrifying position, open- 

 ing their mouths and spreading their lateral mem- 

 branes. When they were still further forced to run 

 and jump they died of fatigue, still holding the 

 terrifying attitude. 



From the observations cited, and from others it 

 results that in the majority of cases the terrifying 

 position is nothing else but a reflex provoked by a 

 general irritation of the entire organism. One can- 

 not exclude the fact that this irritation is provoked 

 by sensations derived through the intermediary of 

 the senses; in these cases the terrifying position has 

 all the appearances of a voluntary action; but the 

 same effect can be obtained by the action of other 

 agents which affect the entire organism (such as 

 fatigue). The terrifying position in our judgment 

 is not a voluntary or conscious action. 



SATURDAY AFTERNOON EXCURSIONS FOR 1919. 



May 10 Geology; Leamy's Lake, just east of 

 Hull ; meet at the end of the Chelsea road electric 

 car line. 



May 17 Zoology; Catfish Bay, just west of 

 Hull along the Ottawa; meet at Eddy's office, end 

 of city street car line in Hull. 



May 31 Economic entomology; Aylmer Park; 

 by Mr. C. B. Hutchings, Department of Agriculture. 



June 7 Ornithology; Beaver Meadow, just west 

 of Hull, along Aylmer road; meet at Eddy's office. 



June 14 Zoology; general; across the Gatineau 

 from Gatineau Point; meet the ferry at Rock- 

 clifle Park. 



June 21 General; Black Rapids by steamer 

 Wanekewan (consult steamboat time-table starts 



about 1.30 p.m.); a reduced rate for the trip will 

 likely be arranged. 



Sept. 20 Fungi and fall botany; Billings' woods; 

 meet at end of Bank street car line on Bank street. 



Sept. 27 Ferns and Mosses; woods about three- 

 quarters of a mile east of Billings' Bridge; meet at 

 end of Bank street car line. 



The time of meeting at the points indicated will 

 be 2.45 p.m., except in the case of the Black Rapids 

 excursion. 



Leaders conversant with the subjects mentioned 

 will be on hand to render assistance. 



Local members and any others interested are given 

 a most cordial invitation to attend. 





