diminutives of conejos

Question

I thought diminutives of conejos should be conejitos. However, answer was "conejillos" Can anybody explain the logic behind?

Thanks in advance.

Answer 1

http://spanish.about.com/od/nouns/a/diminutives.htm

The rules aren't hard and fast as to which suffix is used; the tendency is that words ending in -a, -o or -te form the diminutive by dropping the final vowel and adding -ito or -ita, while -cito or -ecito is added to other words.

Also commonly used as a diminutive suffix are -illo and -cillo along with their feminine equivalents, -illa and -cilla. Other diminutive suffixes include -ico, -cico, -uelo, -zuelo, -ete, -cete, -ín and -iño along with their feminine equivalents. Many of these suffixes are more popular in some regions than others. For example, the -ico and -cico endings are quite common in Costa Rica, and its residents are nicknamed ticos as a result.

Answer 2

It's the same as panecillo meaning a bread roll and I suppose being the diminutive of pan.

It's very obvious that it has same patter with panecillo. I was asking the rule behind.Specifically, I know when to put "ito" or"cito" but do not know when to put"illo". You know what I mean? - hejoni, Jan 29, 2012