insidious creatures

English Language Tests, Intermediate level

ESL/EFL Test #885 [color=blue]“Bedbugs!”, question 8

These tiny creatures were brought under control after the pesticide DDT was used, but when it was banned in 1970, the bugs became extremely prolific.

(a) fascinating
(b) adventurous
(c) insidious
(d) creative

English Language Tests, Intermediate level

ESL/EFL Test #885 [color=blue]“Bedbugs!”, answer 8

These tiny insidious creatures were brought under control after the pesticide DDT was used, but when it was banned in 1970, the bugs became extremely prolific.

Correct answer: (c) insidious
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Are they insidious because they are able to hide under the drapery and they can hibernate themselves for years?

yes. It was because they spread in a hidden way and were harmful to health.